34
21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy Jennifer Morgan 1 and Hala Alameddine 2 1 The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, 2 UMRS 974, UMR7215, Institut de Myologie, Paris 1 UK 2 France 1. Introduction Muscular dystrophies are inherited disorders in which muscle fibers are unusually susceptible to damage, leading to progressive loss of muscle structure and function. Some types of muscular dystrophy affect heart muscles, other involuntary muscles and other organs. The most common form of muscular dystrophy, Duchenne Muscular Dystrophy (DMD), is due to genetic deficiency of the protein dystrophin (Monaco et al., 1985). This protein is one of several partners that interact to link intracellular cytoskeleton to extracellular matrix (ECM) hence consolidating the scaffold necessary for maintaining structural integrity of skeletal muscle fibers. Dystrophin deficiency destabilizes muscle fibers, which become less resistant to contractions leading to muscle fiber necrosis and subsequent regeneration. Skeletal muscle repair, maintenance and regeneration are mediated by muscle-specific stem cells: the satellite cells (Mauro, 1961), located underneath basal lamina of muscle fibers. In DMD muscles, fat and connective tissue often replace muscle fibers in the late stages of muscular dystrophy, indicating that muscle regeneration does not keep up with fiber loss. Defective muscle regeneration could be due to exhaustion of proliferative capacity of satellite cells (Blau et al., 1983; Webster & Blau, 1990) or to environmental factors that are not conducive to their function. The healing process usually includes sequential and overlapping events of muscle fiber degeneration, inflammatory reaction, regeneration and remodeling of ECM components that require tightly regulated orchestration of the interactive cross-talk that conditions the outcome of the regenerative process. Uncontrolled wound-healing, in response to chronic injury and inflammation, results in tissue fibrosis and scarring which impacts on the efficiency of muscle regeneration, hence contributing to the degradation of muscle function. At present, we still have no cure for any form of muscular dystrophy, but medications and therapy can slow the course of the disease to allow people with muscular dystrophy to remain mobile for as long as possible. Nevertheless, experimental therapeutic strategies have been initiated in light of basic and technical advances of skeletal muscle biology and pathophysiology. The description of the muscle regeneration process and the identification www.intechopen.com

Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

  • Upload
    others

  • View
    2

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

21

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental

Factors Influencing Their Efficacy

Jennifer Morgan1 and Hala Alameddine2

1The Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, 2 UMRS 974, UMR7215, Institut de Myologie, Paris

1UK 2France

1. Introduction

Muscular dystrophies are inherited disorders in which muscle fibers are unusually susceptible to damage, leading to progressive loss of muscle structure and function. Some types of muscular dystrophy affect heart muscles, other involuntary muscles and other organs. The most common form of muscular dystrophy, Duchenne Muscular Dystrophy (DMD), is due to genetic deficiency of the protein dystrophin (Monaco et al., 1985). This protein is one of several partners that interact to link intracellular cytoskeleton to extracellular matrix (ECM) hence consolidating the scaffold necessary for maintaining structural integrity of skeletal muscle fibers. Dystrophin deficiency destabilizes muscle fibers, which become less resistant to contractions leading to muscle fiber necrosis and subsequent regeneration.

Skeletal muscle repair, maintenance and regeneration are mediated by muscle-specific stem cells: the satellite cells (Mauro, 1961), located underneath basal lamina of muscle fibers. In DMD muscles, fat and connective tissue often replace muscle fibers in the late stages of muscular dystrophy, indicating that muscle regeneration does not keep up with fiber loss. Defective muscle regeneration could be due to exhaustion of proliferative capacity of satellite cells (Blau et al., 1983; Webster & Blau, 1990) or to environmental factors that are not conducive to their function. The healing process usually includes sequential and overlapping events of muscle fiber degeneration, inflammatory reaction, regeneration and remodeling of ECM components that require tightly regulated orchestration of the interactive cross-talk that conditions the outcome of the regenerative process. Uncontrolled wound-healing, in response to chronic injury and inflammation, results in tissue fibrosis and scarring which impacts on the efficiency of muscle regeneration, hence contributing to the degradation of muscle function.

At present, we still have no cure for any form of muscular dystrophy, but medications and therapy can slow the course of the disease to allow people with muscular dystrophy to remain mobile for as long as possible. Nevertheless, experimental therapeutic strategies have been initiated in light of basic and technical advances of skeletal muscle biology and pathophysiology. The description of the muscle regeneration process and the identification

www.intechopen.com

Page 2: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

410

of the cells responsible for myofiber regeneration led to stem cell therapy being considered as a potential strategy to alleviate muscle deficiency in DMD patients. Alternatively, the identification of gene defects and the sophistication of molecular biology technologies have opened perspectives for gene therapy, either by providing the deficient gene, or by restoring gene function. Other strategies combining both approaches have been considered and imply the correction of patients’ own stem cells before grafting them into the diseased muscles. These promising strategies have been challenged in animal models of muscular dystrophies and although they achieved a certain success, they also identified a number of limitations. Moreover, the failure of myogenic cell grafting to improve muscle function and to restore dystrophin expression in clinical trials of DMD patients, underscored the need to improve the efficiency of cell therapy. Cell environment, which comprises ECM and extracellular matrix deposited factors such as growth factors, cytokines and chemokines, regulate diverse cellular functions. These molecules are metabolized by Matrix MetalloProteinases (MMPs) that play a central role as regulators of tissue microenvironment. In normal situations, precise spatiotemporal repertoires of MMPs balanced by inhibitors, among which are the four Tissue Inhibitors of MatrixmetalloProteinases (TIMPs), regulate extracellular signaling networks and maintain tissue homeostasis. On the contrary, increased MMPs expression or activity has been demonstrated in various disease situations including, practically every known inflammatory disease (Manicone & McGuire, 2008). Such disruption of the dynamic equilibrium between MMPs and TIMPs may affect diverse cellular functions including cell proliferation, migration, adhesion and apoptosis (Holmbeck et al., 2005; Hulboy et al., 1997; Vu & Werb, 2000). In DMD, for example, inflammation and fibrosis are major hurdles in the path of therapeutic strategies (Wells et al., 2002) and their resolution is expected to positively impact on the efficiency of any form of therapy, but more specifically, on the efficiency of cell therapy. Indeed, myogenic stem cells have limited migratory capacity, which is further aggravated by excessive proliferation of connective tissue. Therefore, improving the efficiency of cell therapy could be achieved either by myogenic cells better able to digest accumulated ECM components or, alternatively, by other types of stem cells that can be recruited from a resident or circulating pool and are capable of migrating through one or several tissue barriers to home into skeletal muscles. In this chapter, we consider the use of stem cell therapy to treat muscular dystrophies. By going through the different cell types that have been used, we will try to define the best cell type to use, how to handle and expand these cells before transplantation and the best route of delivery. Moreover, the possibility of using genetically-modified autologous stem cells for transplantation will be presented. This would only be possible if the stem cell had not been deleteriously affected by the dystrophic environment. Finally, we will consider the host environment as a modulator of cell behaviour and the dual role MMPs play in the control of this environment and their impact on transplanted cells migration, differentiation and self-renewal.

2. Potential therapies for duchenne muscular dystrophy

Muscular dystrophies are a heterogeneous group of inherited neuromuscular disorders, including X-linked recessive as in DMD, autosomal recessive as in limb–girdle muscular dystophy type 2, or autosomal dominant as in facioscapulohumeral muscular dystophy, myotonic dystrophy, and limb–girdle muscular dystophy type 1 (Emery, 2002). In the last two decades, different types of dystrophies have been genetically characterized. The most

www.intechopen.com

Page 3: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

411

frequent and most severe form, DMD, is a progressive, incurable X-linked recessive disorder that affects 1 in 3500 newborn boys and leads to death in the second or third decade of life (Bushby et al., 2010). DMD patients lack the protein dystrophin while in-frame mutations of the same gene led to expression of a partially functional protein, resulting in the milder Becker muscular dystrophies (BMD). As a result of the absence of dystrophin, muscle fibers of DMD patients undergo necrosis followed by regeneration which, in the long run, fails to keep up with the recurrent cycles of degeneration-regeneration and muscle fibers are lost and replaced by fibro-fatty tissue. Interruption of these cycles can be achieved by dystrophin restoration to the muscle fiber membrane (Meng et al., 2011a). Several strategies can now be used to restore dystrophin to the muscle fibers of affected patients. They include virally-mediated gene therapy, read-through of stop codons, up-regulation of compensatory genes, or skipping of mutated dystrophin exons to give rise to a shorter, but still functional dystrophin protein. However, all of these have possible drawbacks (reviewed (Goyenvalle & Davies, 2011; Guglieri & Bushby, 2010; Hoffman et al., 2011; Sugita & Takeda, 2010)). Either gene therapy, or application of antisense oligonucleotides to skip mutated dystrophin exons, requires that the patient has sufficient muscle fibers remaining for treatment. In addition, exon skipping is mutation-dependent and not all patients have mutations amenable to this approach.

3. Stem cell therapy for the treatment of DMD

The concept of a cell-based therapy to alleviate loss of muscle structure and function in

muscular dystrophy originated with the observation of the intrinsic ability of myogenic

stem cells to fuse either with each other to form multinucleated myofibers, or with necrotic

muscle fibers to form mosaic fibers. In theory, functional correction could be achieved in

DMD by the generation of either hybrid muscle fibers where the donor nuclei provide the

missing gene product and/or the regeneration of normal myofibers from the fusion of

normal donor cells to replace lost muscle fibers. Cell therapy was the first biologically based

approach applied for the treatment of DMD and required the use of animal models to

explore the beneficial effects of this therapy. The ability of cultured myogenic cells to

regenerate new muscle fibers, that reconstitute the same architectural organization of the

original muscle and induce functional recovery, has been validated using an experimental

model of irreversible injury to adult rodent muscle associating auto-transplantation of

skeletal muscle to X-irradiation (Alameddine et al., 1989; Alameddine et al., 1991; Alameddine

et al., 1994).

3.1 Stem cells

Stem cells are defined as cells that can both self-renew and give rise to more differentiated cell type, whereas precursor cells do not have the ability to self-renew. Both cell types present a great advantage for the treatment of muscular dystrophies as they could repair segmental necrosis and also give rise to regenerated muscle fibers to replace those that are lost as a consequence of the dystrophy. They could therefore be effective at later stages of the dystrophy, when muscle fibers have already been lost. Donor cells derived from a normal individual will automatically express dystrophin when they differentiate into a muscle fiber, but the quantity and distribution of dystrophin within the fiber will depend on the number of donor myonuclei and the size of segments of the fiber to which they

www.intechopen.com

Page 4: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

412

contribute. However, the recipient and donor will need to be HLA-matched, so that stem cells from one normal donor could not be used to treat all patients.

Although many different stem or precursor cells have been shown to contribute to muscle regeneration in animal models, many of these give rise to only limited amount of muscle, for example haematopoietic stem cells (Ferrari et al., 1998) and mesenchymal stem cells (Chan et al., 2006; Meng et al., 2010). Satellite cells are the archetypal skeletal muscle stem cell, but they are by definition quiescent cells underneath the basal lamina of muscle fibers and it would be impossible to obtain enough of them for therapeutic application. However, the progeny of satellite cells, muscle precursor cells or myoblasts, could be prepared in sufficient quantity for transplantation. In this review, therefore, we will focus on cells that can be expanded in culture and that have been shown to contribute to muscle regeneration- myoblasts, cells derived from blood-vessel associated pericytes (termed mesoangioblasts) and skeletal muscle-derived AC133+ cells. There are several recent reviews on stem cells to treat muscular dystrophies, which cover most of the cell types that have been studied (Meng et al., 2011a; Negroni et al., 2011; Palmieri et al., 2010; Skuk & Tremblay, 2011; Tedesco et al., 2010).

3.2 Models and markers

To investigate the potential contribution of a particular cell type to muscle regeneration, the standard experiment is to graft the cells into an animal model of DMD and measure their contribution to skeletal muscle fibers, which may be quantified by either counting the number of dystrophin-positive fibers, or measuring the amount of dystrophin on western blot. Several animal models of DMD exist but the most widely-used is the dystrophin-deficient mdx mouse (Bulfield et al., 1984) used in 1,940 pubmed publications, as of 21 July 2011. Other models of DMD include the golden retriever muscular dystrophy (GRMD also known as Canine X-linked Muscular Dystrophy CXMD) dog and zebrafish (reviewed (Banks & Chamberlain, 2008; Collins & Morgan, 2003)). Mouse and dog models have been used to investigate different potential therapies for DMD, including precursor/stem cell transplantation (Nakamura & Takeda, 2011). However, when grafting cells from one donor to another, the host must either be immunodeficient or immunosuppressed. Therefore, mdx mice with different types of immunodeficiency have been used as hosts in cell transplantation experiments, including mdx nu/nu (Boldrin et al., 2009; Collins et al., 2005; Partridge et al., 1989), SCID mdx (Benchaouir et al., 2007; Dellavalle et al., 2007; Torrente et al., 2004), Rag-/- mdx (Gerard et al., 2011), or mdx mice immunosuppressed with FK506 (Kinoshita et al., 1994b), but to what extent these different hosts are comparable, being on different genetic backgrounds and having different mechanisms and degrees of immunodeficiency, has not been ascertained (reviewed (Meng et al., 2011b)). Immunodeficient mice are more convenient to work with than mice that have to be immunosuppressed and seem to permit greater donor-myoblast-derived muscle regeneration (Partridge et al., 1989). However, it is important to consider the effect of the immunological system on donor-derived muscle regeneration, as DMD patients will not be immunodeficient. Non-dystrophic mice or monkeys, whose muscles have been injured to mimic the degeneration and regeneration that occurs in dystrophic muscles, have also been used as recipients to test cell transplantation (Cooper et al., 2001; Morgan et al., 2002; Sacco et al., 2008; Skuk et al., 1999), as have mice that model different types of dystrophy, e.g. sarcoglycan (Sampaolesi et al., 2003) and dysferlin-deficient mice (Diaz-Manera et al., 2010).

www.intechopen.com

Page 5: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

413

A major consideration when using both dystrophic and non-dystrophic animal models to test stem cells is that the host muscle usually has to be injured in some way to enhance donor cell engraftment. This is surprising, as the muscle fiber degeneration and regeneration that is already occurring in dystrophic muscle would be thought to be sufficient to promote donor stem cells to contribute to muscle regeneration. However, muscle fiber necrosis is often focal and only cells located nearby contribute to regeneration (Yokota et al., 2006). Therefore, if the transplanted stem cell is located a distance away, it may not either receive the correct signals, or be able to migrate to the damaged fibers. As many of these injury regimes are very severe, for example, cryoinjury (Brimah et al., 2004; Irintchev et al., 1997; Negroni et al., 2009) or use of snake venoms (Lefaucheur & Sebille, 1995; Silva-Barbosa et al., 2005) to induce degeneration and regeneration in host muscles, they could not be used in patients. Even in dystrophin-deficient mdx nu/nu host mice, satellite cells contribute little, if any, to muscle regeneration (Boldrin et al., 2009; Collins et al., 2005) although myoblasts contribute to muscle regeneration to a greater extent ( Morgan et al., 2002; Partridge et al., 1989). This poor contribution of donor cells to muscle regeneration is likely to be due to the fact that mdx mouse muscles, in contrast to those of DMD patients, regenerate very well. We therefore blocked muscle regeneration in mdx muscles by applying local high doses of radiation, to obtain a model more similar to DMD, in which the muscle degenerates and atrophies but does not regenerate (Morgan et al., 1990; Pagel & Partridge, 1999; Wakeford et al., 1991). If host muscle is irradiated with 18 Gy before donor cell grafting, satellite cell and myoblast contribution to muscle regeneration is significantly augmented (Boldrin et al., 2009; Collins et al., 2005; Morgan et al., 2002). This may be due to prevention of competition from local host stem or satellite cells, as irradiated mdx muscles do not regenerate (Pagel & Partridge, 1999; Wakeford et al., 1991) unless a severe injury, e.g. injection of snake venom notexin, is imposed on them, which evokes rare radiation-resistant stem cells to regenerate (Gross & Morgan, 1999; Heslop et al., 2000). Other models that could be used to test whether a wholly or partially emptied satellite cell niche is necessary for efficient donor muscle stem cell engraftment include Pax7 knockout mice (Seale et al., 2000) that lack satellite cells, or the mdx mouse that also lacks telomerase (mTR) activity and therefore shows a reduction in the regenerative capacity of myogenic stem cells (Sacco et al., 2010).

Another important consideration is the marker(s) to be used to assess the contribution of donor cells to regenerated muscle fibers and/or satellite cells (reviewed (Meng et al., 2011a)). As the aim is to produce dystrophin in host muscle fibers, it is sensible to quantify dystrophin restoration in the host muscles (Partridge et al., 1989). Because “revertant” fibers that spontaneously express dystrophin are present in animal models of DMD (Hoffman et al., 1990) and in DMD patients (Arechavala-Gomeza et al., 2010) and because clusters of revertant fibers increase in number with time (Hoffman et al., 1990; Yokota et al., 2006), revertant fibers must be controlled for, particularly if dystrophin is being used alone as a marker of donor-derived muscle fibers and especially in time course studies. If grafting human cells into mouse, a human-specific dystrophin antibody (e.g. Novocastra Dys3 (Brimah et al., 2004)) may be used, that will not identify mouse revertant fibers. Because of the existence of revertant fibers, many groups use a second marker of either muscle fibers or cells of donor origin, e.g. by using donor cells from genetically-modified mice, e.g. myosin 3f nLacZ-E, that is expressed in myonuclei of donor origin, Myf5 nLacZ/+ that is expressed in satellite cells of donor origin (Collins et al., 2005), or ubiquitously (Morgan et al., 2002) or

muscle-specifically (Kinoshita et al., 1994a) expressed -gal or GFP. Donor cells may

www.intechopen.com

Page 6: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

414

alternatively be marked in culture with constructs expressing a marker protein (Blaveri et al., 1999; Cousins et al., 2004; Diaz-Manera et al., 2010; Morgan et al., 2002). However, caution should be used in interpreting results, as GFP is notoriously difficult to use in skeletal muscle (Jackson et al., 2004), some markers spread further along a mosaic muscle fiber than others (Blaveri et al., 1999) and others are switched off in vivo (Boldrin et al.,2009).

3.3 Contribution of locally-delivered donor stem cells to muscle regeneration.

A large body of evidence can be found in the literature to illustrate the contribution of myoblasts to skeletal muscle regeneration, although the number of donor-derived muscle fibers is limited (Figure 1). However, the host muscle environment that permits regeneration from myoblasts of mouse and human origin appears to be different, although a comparative experiment to establish this point has not been performed: human myoblasts form more muscle within host muscles that have been cryoinjured prior to grafting (Brimah et al., 2004), whereas mouse myoblasts form significantly more muscle in irradiated host muscles (Boldrin and Morgan, manuscript in preparation).

Different muscle injury models used for intra-muscular grafting of putative muscle stem cells may also give rise to discrepancies between groups. Some groups have grafted cells into muscles of non-dystrophic mice that had been cryo-injured immediately prior to grafting (Brimah et al., 2004; Cooper et al., 2001; Ehrhardt et al., 2007), but others grafted cells into muscles of mdx SCID mice that had been injected 48 hours previously with cardiotoxin, (Dellavalle et al., 2007) or into cryo–injured muscles of immunodeficient Rag2-/-

gamma chain-non-dystrophic mice (Pisani et al., 2010). Vauchez et al. grafted into muscles of non-dystrophic SCID mice, injuring the muscles prior to grafting by a combination of irradiation and notexin (Vauchez et al., 2009); Zheng et al. grafted cells into muscles of SCID mice that had been injured by cardiotoxin one day previously (Zheng et al., 2007). How these different injury regimes mimic the dystrophic muscle environment and to what extent the local environment, genetic background and immunological status of the host mouse affect muscle stem cell behavior are important to determine, for the identification of robust methodologies which could reliably be used for therapeutic trials in muscular dystrophies.

Interestingly, although they contributed to much muscle regeneration after intra-arterial injection, pericytes only gave rise to very small numbers of muscle fibers after intra-muscular transplantation: CD56+/ALP- cells (satellite-cell derived myoblasts) gave rise to more muscle than CD56+/ALP+ cells (pericytes), but CD56-/ALP- cells, taken to be fibroblasts, made very few donor muscle fibers (Dellavalle et al., 2007). Meng et al. also found that both CD56+ and CD56- skeletal muscle-derived cells contributed to muscle regeneration, CD56+ cells making significantly more muscle than either CD56-, or non-fractionated cells after intra-muscular transplantation. CD56+ cells contributed predominantly to nuclei inside the basal lamina of muscle fibers, i.e. within muscle fibers and/or satellite cells. But CD56- or non-sorted cells contributed to significantly more nuclei outside the basal lamina, confirming that there were more non-myogenic cells within CD56- cell population (Meng et al., 2011b). Zheng et al showed that human skeletal muscle-derived CD56+ cells that also expressed CD34 and CD144 (myoendothelial cells) contributed to more muscle regeneration than did CD56+/CD34-/CD144- cells (myoblasts) (Zheng et al., 2007) in contrast to the findings of Meng suggesting that pericytes, rather than endothelial cells, are the major CD56- contributor to muscle regeneration (Meng et al., 2011b)

www.intechopen.com

Page 7: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

415

Fig. 1. 7 µm transverse cryosection of mdx nu/nu host tibialis anterior muscle, that had been cryoinjured and grafted with 5 x 105 human skeletal muscle-derived stem cells 4 weeks previously. Stained with antibodies to human spectrin and human specific lamin a/c, that recognise muscle fibers and nuclei of human origin respectively. Counterstained with DAPI. Bar= 50 µm. (Courtesy of Dr Jinhong Meng).

3.4 Contribution of systemically-delivered donor stem cells to muscle regeneration

The contribution of blood vessel-derived cells (both from skeletal muscle and embryonic

dorsal aorta) to skeletal muscle regeneration in vivo after their systemic delivery has been

demonstrated in several publications (Dellavalle et al., 2007; Sampaolesi et al., 2003;

Sampaolesi et al., 2006)(reviewed (Sancricca et al., 2010)), however these promising findings

could not be replicated by others (Meng et al., 2011b). For long-term efficacy, it would be

useful to know whether a grafted pericyte self-renews to give more functional pericytes and

if so, what contribution these have to further muscle regeneration. Another stem cell that is

promising for systemic delivery to skeletal muscle is the AC133+ cell, derived from either

blood (Torrente et al., 2004), or skeletal muscle (Benchaouir et al., 2007).

3.5 Death and proliferation of grafted cells

Donor myoblasts die on intra-muscular grafting (Beauchamp et al., 1999; Skuk et al., 2002;

Smythe et al., 2000) possibly as a result of one or a combination of various factors: cell

dissociation, trophic factor withdrawal, oxidative stress, excito-toxicity, hypoxia and,

possibly, anoikis (reviewed (Gerard et al., 2011; Skuk & Tremblay, 2011)) and much effort

has been expended to prevent this death (reviewed (Skuk & Tremblay, 2011)). Recent

experiments have indicated that the number and density of cells transplanted into one site

intra-muscularly may also be critical factors influencing their survival and proliferation

(Pellegrini & Beilharz, 2011) and that more cells may not give rise to more muscle fibers of

donor origin (Pellegrini & Beilharz, 2011; Praud et al., 2003; Rando & Blau, 1994), possibly

www.intechopen.com

Page 8: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

416

because cells in the centre of dense pellets undergo more apoptosis. But another theory is

that the cells that die are irrelevant, as those that survive proliferate extensively under

appropriate environmental conditions, to reconstitute the host muscle (Beauchamp et al.,

1999). It is however unclear whether other types of muscle stem cell undergo death after

transplantation, or if they proliferate within the grafted muscles.

3.6 Signals inducing muscle stem cells to contribute to muscle regeneration

Intra-arterial injection of mesoangioblasts has shown that only a very small percentage reach

downstream skeletal muscles, most being trapped in the filter organs. To enable cells to exit

blood vessels, the vessels must express the appropriate adhesion molecules for that cell type.

Molecules that have been shown to be important for mesangioblast extravasation into skeletal

muscle include HMGB1, SDF-1 and TNF- (Palumbo et al., 2004). Expression of the adhesion

molecules L-selectin and alpha 4 integrin on mesoangioblasts improved their migration into

skeletal muscle (Galvez et al., 2006). Pre-treatment with nitric oxide was shown to augment the

positive effects of TNF-, TGF- and VEGF on mesangioblast migration (Sciorati et al., 2006).

Once the donor stem cells have entered the muscles, they must migrate to sites of injury, proliferate to give a pool of muscle precursor cells and then differentiate to form muscle fibers, either by fusing with each other or by repairing necrotic segments of dystrophic fibers. This will require them to respond to a new series of signals, which might be more appropriate for satellite cells than for stem cells.

In order to have long term benefit, the donor stem cells muscle repopulate a stem cell niche

within the muscle and must retain the properties of a functional muscle stem cell within this

niche. It is not clear if pericytes within their niche contribute to muscle regeneration, so the

best niche to occupy would be the satellite cell niche. However, efficient repopulation of any

niche, for example, the satellite cell niche, would only be possible if it were emptied as a

consequence of the dystrophy and if the niche environment remains permissive for donor-

derived stem cell function. As satellite cell of donor origin are most commonly found on

fibers containing myonuclei of donor origin, they may not be called upon to regenerate, as

the fiber on which they are situated will already have been strengthened by the new

dystrophin and may not undergo further necrosis, at least at the sites where dystrophin is

expressed. A means of activating these cells and drawing them towards more distant areas

of injury is therefore required to enable them to respond to future muscle fiber necrosis

elsewhere within the muscle.

3.7 Autologous cell transplantation

An attractive proposition for treating muscular dystrophies is to use genetically-corrected autologous stem cells. The use of autologous stem cells should circumvent the need for immunosuppression, although tissue culture components or expression of novel protein isotypes in vivo may evoke an immunological reaction. But, if the stem cells are skeletal-muscle derived, their function may be impaired by either the primary genetic defect, or secondary environmental consequences of the primary defect.

In some muscular dystrophies, the gene responsible is not expressed in satellite cells (reviewed (Morgan & Zammit, 2010)); for example, dystrophin is not expressed in satellite

www.intechopen.com

Page 9: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

417

cells (or other types of muscle stem cell), so satellite cells in DMD muscles would therefore be expected to have normal function. However, the satellite cells may have undergone many divisions in their previous attempts to repair the dystrophic fibers and could therefore be close to senescence (Decary et al., 1996; Decary et al., 1997; Webster & Blau, 1990). They would consequently be of little use for autologous therapy, as they would undergo insufficient divisions in vitro to be genetically modified and then to proliferate following transplantation. But although human myoblasts are exhausted in DMD (Decary et al., 1996; Decary et al., 1997; Webster & Blau, 1990), mdx satellite cells do not appear to suffer the same consequence of dystrophin deficiency (Bockhold et al., 1998). Recent evidence has indicated that mdx satellite cells are highly functional following transplantation into irradiated mdx nu/nu muscles (Boldrin and Morgan, unpublished observations). So although satellite cells may not be lost in DMD (reviewed (Boldrin et al., 2010)), their function is compromised, which may be due to telomere shortening leading to reduced proliferative capacity, or a change in the timing or extent of differentiation. However, caution must be taken when comparing mdx and DMD cells, as there are differences in telomere biology between mice and humans: inbred mouse strains have extremely long telomeres (20–150 kilobases) compared with humans (up to 15 kilobases) (Bekaert et al., 2005) and telomerase activity is lower in human compared to mouse cells (reviewed (Mather et al., 2011)).

It is unclear whether skeletal muscle-resident cells other than satellite cells contribute to muscle regeneration in muscular dystrophies, or even to maintenance and repair of normal muscle. If they had not actively contributed to the cycles of degeneration and regeneration that occur in DMD, they would be capable of many more divisions than the satellite-cell derived myoblasts and therefore be a more attractive candidate for autologous therapy. However, if they do not contribute to muscle regeneration in DMD, why do they not do so? And why would they be effective after transplantation, if they are not functional in situ? Possibly they are not recruited to muscle fiber maintenance and regeneration when they are in their natural niche in vivo, but do so after they encounter the site of muscle damage after either intra-muscular or systemic injection.

An ideal autologous stem cell would be derived non-invasively, e.g. from the peripheral blood, or a skin biopsy. However, to date there is only one report of blood-derived stem cells that make reasonable amounts of muscle after their systemic delivery (Torrente et al., 2004).

3.7.1 Genetic modification of autologous cells.

Genetic correction of autologous stem cells has been successfully used as a therapeutic option in other conditions and encouraging preclinical results have also been recently obtained in animal models of DMD (Meregalli et al., 2008). However key questions that need to be resolved before this approach could be used in DMD include the optimal vector configuration and the safety profile of the gene delivery methodology. Lentiviral vectors efficiently infect quiescent cells, including stem cells (S. Li et al., 2005) and give long-term, heritable, gene expression because they integrate into the host genome. Drawbacks with lentiviral vectors include possible gene silencing, or mutagenesis (Wilson & Cichutek, 2009), due to the site at which the virus inserts into the host genome. Although lentiviruses integrate preferentially into active transcription sites (Ciuffi, 2008) the development of third generation lentiviruses with advanced SIN design (Bokhoven et al. 2009), physiological

www.intechopen.com

Page 10: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

418

promoters and cell-specific envelope proteins (Rahim et al., 2009) and enhancer-less regulatory elements, e.g. the ubiquitously acting chromatin opening element (UCOE) (Montini et al., 2006; Zhang et al., 2007) should circumvent these problems.

A lentiviral vector has been used to insert a 6.8 kb dystrophin mini gene (S. Li et al., 2005), to

give rise to a shorter dystrophin protein in regenerated muscle fibers. While these

engineered mini-dystrophins appear to retain most of the functional properties of full-length

dystrophin, they nevertheless miss important domains, such as the nitric oxide synthase

anchoring domain (Lai et al., 2009). Considering the cloning capacity of lentiviral vectors

(up to 10kb (M. Kumar et al., 2001)), it should be possible to further optimise a vector so that

it accommodates most of the functionally relevant coding region of dystrophin. An optimal

dystrophin construct in a lentiviral vector could be used to treat patients with different

mutations, in contrast to the U7 constructs, which, although they can be placed in a

lentiviral vector and induce dystrophin expression in stem cells in vitro and following their

transplantation in vivo (Quenneville et al., 2007), are mutation-specific.

4. Matrix Metalloproteinases: modulators of microenvironment and cell function in skeletal muscles

The Matrix Metalloproteinases (MMPs) are a large group of zinc-dependent extracellular

endopeptidase proteinases within the Metzincin superfamily of protease that also includes a

disintegrin and metalloproteinases (ADAM) and ADAM with thrombospondin motifs

(ADAMTS). MMPs family comprises 23 members in humans that share common modular

domains and form 5 main sub-groups based on their structure and substrate: collagenases,

gelatinases, matrilysins, stromelysins and membrane-type (Figure 2). With the exception of

membrane bound MMPs, the other members of the group are secreted in the extracellular

space where they are present in latent forms and become activated by other proteases or in

response to signaling events. Their activity is regulated at the transcriptional and post-

transcriptional levels as well as by their physiological inhibitors, Tissue Inhibitors of Matrix

Metalloproteinases (TIMPs). Collectively, they are able to degrade all components of the

ECM. Initially confined to the degradation of ECM, their function has progressively evolved

and they are now regarded as major regulators of tissue environment and cell functions

(Murphy, 2010; Rodriguez et al., 2010). They modulate cell proliferation, adhesion,

migration and signaling (Fanjul-Fernandez et al., 2010).

4.1 Matrix Metalloproteinases in remodeling muscles

The adult skeletal muscle is a very stable tissue yet it is endowed with a high capacity to adapt to modification of functional demands, trauma or disease. In normal situations, the dynamic equilibrium between MMPs and TIMPs maintains homeostasis of ECM that provides a dynamic support and stores a number of growth factors that are liberated during ECM remodeling. In response to remodeling situations, dysregulation of this balance occurs in favor of MMPs, to allow necessary hydrolysis of ECM which results in the liberation of neo-epitopes from basement membrane components, as well as various growth factors and signaling molecules that modulate cell response to environmental modifications. Such imbalance may be temporary and the equilibrium is restored upon the disappearance of remodeling stimuli.

www.intechopen.com

Page 11: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

419

Fig. 2. Structural domains and nomenclature of the matrix metalloproteinases, A: Schematic

representation of modular domains composing MMPs which are translated as inactive

zymogens with an amino terminal signal peptide (SP), a pro-domain which folds over the zinc

ion, in the catalytic site, to maintain latency (Pro), a catalytic domain that carries zinc at the

active site, a hemopexin that confers the specificity to and interaction with the substrates or

inhibitors (TIMPs) and presents the substrate to the catalytic site via a highly flexible hinge

domain. Membrane-type (MT-) MMPs are anchored to the membrane either with a

hydrophobic domain and a short cytoplasmic tail (Type I transmembrane protein) or with a

glycosyl-phosphatidyl-inositol (GPI) domain. Gelatinases A and B also contain three collagen-

binding fibronectin type II repeats within the catalytic domain and MMP-9 has an additional

Serine-Threonine and proline rich O-Glycosylated domain. Some MMP have a furin-like motif

www.intechopen.com

Page 12: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

420

between the pro- and catalytic domains that allow their activation before they are secreted or

localize to the membrane. MMP- 22 has a cysteine/proline rich, interleukin-1R domain and an

Immunoglobulin–like domain. Compiled from (Bourboulia & Stetler-Stevenson, 2010; Fanjul-

Fernandez et al., 2010; Rosenberg, 2009; Sternlicht & Werb, 2001).

In skeletal muscles, normal muscle development, limb immobilisation, electrical stimulation and muscle injury are all remodeling situations characterized by MMPs/TIMPs dysregulation. However, the nature of MMPs that is upregulated and the time frame of this upregulation depend, a great deal, on the model used. Immobilization or unloading, that result in muscle fiber atrophy, induce upregulation of both MMP-2 and MMP-9 and downregulation of TIMPs (Berthon et al., 2007; Giannelli et al., 2005; Reznick et al., 2003; Stevenson et al., 2003; Wittwer et al., 2002) (Berthon et al., 2007; Giannelli et al., 2005; Reznick et al., 2003; Stevenson et al., 2003; Wittwer et al., 2002 ) but only MMP-2 is active (Liu et al., 2010). Whereas a single bout of degeneration-regeneration, induced by experimental injury to the muscle, also results in upregulation of these two proteases but the time frame and intensity differ according to the type/extent of injury (Ferre et al., 2007; Frisdal et al., 2000; Kherif et al., 1999). In a cardiotoxin injury model that induced massive myofiber necrosis, gelatinase activity progressively increased and peaked at day 7, when muscle fiber formation was the most active. It then returned to normal at later stages. This increase was due to simultaneous and consecutive steps of gelatinases regulation- both expression and activation. Within hours after tissue injury, MMP-9 was induced in the tissue that expressed only MMP-2 in the normal situation. It correlated with inflammatory cells infiltration of necrotic muscle fibers that exhibit high gelatinase intracellularly, in contrast to pericellular localization of gelatinase in normal muscles (Figure 3). Simultaneously, MMP-2 expression and activation decreased within the first 24 hours and was followed by a progressive reconstitution of these forms afterwards. MMP-9 transcripts localized to

Fig. 3. In situ zymography of normal and cardiotoxin injured muscle 3 days after injury. In normal muscles, gelatinase activity (shown in white) localized to the endomysium and mononucleated cells present at the vicinity of muscle fibers. In injured muscles, gelatinase activity localizes to inflammatory cells. At early time points when necrotic muscle fibers are invaded by inflammatory cells, gelatinase activity is detected within degenerating muscle fibers that are invaded by inflammatory cells. Original magnification, X40 (Alameddine, Unpublished results).

www.intechopen.com

Page 13: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

421

inflammatory cells and mononucleated cells at satellite cell position (Kherif et al., 1999). The possibility that myogenic cells upregulate MMP-9 has been confirmed recently. When exposed to debris of damaged myotubes, the myogenic cells upregulated MMP-9, monocyte chemoattractant protein (MCP)-1 and other factors necessary for angiogenesis, tissue regeneration, and phagocyte recruitment (Dehne et al., 2011). Latent MT1-MMP (63kDA), which contributes with TIMP-2 to MMP-2 activation, is processed to its active (50kDa) form that retained its ability to process MMP-2 and was preceded by TIMP-2 decrease (Barnes et al., 2009). MMP-3 and TIMP-1 transcripts were also shown to be upregulated within the first 24 hours following cold injury. TIMP-1 started to decrease 72 hours post injury and early increase was followed by a decrease of active MMP-3 (Urso et al., 2010).

4.2 Matrix Metalloproteinases in dystrophic muscles

In dystrophic mdx and CXMD muscles, MMP-2 and MMP-9 are found in muscle extracts whereas only MMP-2 is found in normal muscles (Fukushima et al., 2007; Kherif et al., 1999). MMP-9 is upregulated in both muscles and serum of mdx mice (H. Li et al., 2009) throughout their lifespan (Alameddine et al., unpublished results). MT1-MMP, TIMP-1 and TIMP-2 are also upregulated in CXMD muscles and gelatinase activity localized to necrotic fibers and endomysium, demonstrated by in situ zymography (Fukushima et al., 2007). Differences in MMP expression and activity patterns detected in different adult mdx muscles - gastrocnemius, soleus and diaphragm- led Bani (Bani et al., 2008) to hypothesize that the microenvironment of distinct skeletal muscles may influence a particular kinetic pattern of MMP activity, which ultimately favors persistent inflammation and myofiber regeneration at different stages of the myopathy in mdx mice. Gene array analysis revealed profound modification of mRNA levels of several MMPs and other associated proteins in gastrocnemius and tibialis anterior muscles of mdx mice. MMP-3, -8, -9,-10,-12, -14 and -15 Adamts2 and Timp-1 mRNA levels are increased, MMP-11 as well as Adamts1, Adamts5, Adamts8 and Timp-2 and Timp-3 were downregulated (A. Kumar et al., 2010).

In DMD muscles, TIMP-1, TIMP-2 and MMP-2 transcripts are upregulated and MMP-2 activity is increased (von Moers et al., 2005). TIMP-1 levels, usually increased in the serum and plasma of patients with fibrotic diseases, are elevated in serum, plasma, and muscle

extracts of muscular dystrophy patients and animal models. It correlated with TGF1 levels in DMD and in congenital muscular dystrophy (CMD) patients but not with Becker muscular dystrophy patients (Sun et al., 2010). In muscle tissue from dystrophin deficient

and LAMA2-mutated muscular dystrophy patients, pro-fibrotic TGF- is increased partly through a positive autocrine feedback loop and is released from decorin that is degraded by MMP-2. DMD fibroblasts have been shown to produce more soluble collagen, biglycan,

decorin, TGF- and MMP-7 and less MMP-1 than normal fibroblasts. TGF- is known to modulate the ability of cells to synthesize various ECM components and was shown to modify the protein pattern produced by DMD fibroblasts upon their transformation to myofibroblasts. It increased MMP-7 thought to contribute to fibrosis (Fadic et al., 2006; Simona Zanotti et al., 2010; S. Zanotti et al., 2007).

In Emery-Dreifuss muscular dystrophy, screening of MMP-2, MMP-9 and MT1-MMP levels in the serum showed an increase of MMP-2 levels in both the autosomal and X- linked forms, suggesting it may serve as biomarker for the detection of cardiac involvement in patients with no subjective cardiac symptoms (Niebroj-Dobosz et al., 2009).

www.intechopen.com

Page 14: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

422

4.3 MMPs and inflammation in the development of fibrosis

End-stage DMD muscles are characterized by an almost complete disappearance of muscle

fibers and their replacement by fibro-fatty tissue. Although DMD is not a fibrotic disease per se,

their muscle biopsies are generally characterized by excessive production, deposition, and

contraction of extracellular matrix. This accumulation results from factors, produced in

diseased muscles, that influence the normal balance between production and/or hydrolysis of

ECM components. Clearly, structural and functional changes of tissue microenvironment in

dystrophic muscles are not equivalent to those that accompany normal muscle development.

The permanent induction of wound–healing response with its inflammatory component may

be essential contributors to the development of fibrosis in dystrophic muscles. Acute or

chronic inflammation includes exudation of plasma proteins, recruitment of leukocytes and

activation of cell and plasma derived inflammatory mediators as well as increased expression

of MMPs (Manicone & McGuire, 2008). When inflammation is continuous or excessive, it is

thought to contribute to tissue injury, organ dysfunction or chronic disease states. Inversely,

decrease of MMP activity has been incriminated in the development of fibrotic conditions.

Decreased MMP activity may result from dysregulation of the balance between MMPs and

TIMPs. Upregulation of MMPs or downregulation of TIMPs activity could be applied for

resolution of tissue fibrosis (reviewed (Hemmann et al., 2007)).

Experimental evidence shows that inflammatory cells such as macrophages, eosinophiles and T lymphocytes, the major infiltrating cell types, contribute to increased fibrosis (J. Morrison et al., 2000). Inflammatory cells produce cytokines/chemokines that regulate MMPs expression. In their turn, MMPs modulate the activities of cytokines and their receptors at the cell surface. The list of validated ECM components, growth factors (receptors and binding proteins) and cytokines/chemokines substrates is compiled in table 1.

Studies using gene microarrays have demonstrated that dystrophic muscles are characterized by an inflammatory “molecular signature”, in which CC chemokines are prominent (Y. W. Chen et al., 2000; Y. W. Chen et al., 2005; Porter et al., 2003; Porter et al., 2002). Similarly, CC chemokines are greatly upregulated in normal skeletal muscles after experimental injury (Hirata et al., 2003). CC chemokine receptors (CCRs 1, 2, 3, 5) and

ligands (macrophage inflammatory protein-1, RANTES) are expressed at higher levels in dystrophic than in wild-type muscles across age groups (6, 12, and 24 wk). Moreover, chemokine ligand expression and muscle inflammation are significantly higher in dystrophic diaphragms than in limb muscles of the same animals. In vitro, CCR1 is constitutively expressed by myotubes formed from primary myoblasts derived from diaphragm muscles. Stimulation of myotubes by proinflammatory cytokines (tumor

necrosis factor-, interleukin-1, interferon-) found within the in vivo dystrophic muscle environment, upregulates CCR1 in mdx and wild-type myoblast cultures, and also increases expression of its ligand RANTES to a significantly greater degree (Demoule et al., 2005).

In damaged muscles, various cytokines and growth factors are also released during necrosis and regeneration of muscle fibers. The most widely documented pro-fibrotic agent that is

over-expressed in dystrophic muscles is TGF- It is upregulated in dystrophic muscles, after invasion of the damaged muscle by inflammatory cells (Y. W. Chen et al., 2005; Zhou et

al., 2006) that were shown to express TGF-mRNA although these cells may not be the sole contributors to its production (Bernasconi et al., 1999; Gosselin et al., 2004).

www.intechopen.com

Page 15: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

423

Enzyme Enzymes ECM substrates Growth factors & Cytokines/Chemokines

Secreted-type MMP

Collagenases

Interstitial collagenase MMP-1

Aggrecan; Collagens I,- III, VII, VIII, X, XI; Entactin; Fn; Gelatins; Ln; Link protein; Tenascin; Vn; Perlecan;

CTGF; IL1-; IGFBPs; MCP-1, MCP-2, MCP-3, MCP-4; TNF-

Neutrophil collagenase MMP-8

Aggrecan; Collagens I- III; Gelatins; link protein

LIX/CXCL5

Collagenase-3 MMP-13 Aggrecan; Collagens I-III,VI, IX, X, XIV; Fibrillin; Fn; Gelatins; Osteonectin; Ln; Perlecan

CTGF; MCP-3/CCL7, TGF-; SDF-1/CXCL12

Collagenase-4 MMP-18 Collagen I

Gelatinases

Gelatinase A MMP-2 Aggrecan; Collagens I, III-V, VII, X- XI; Decorin; Elastin; Entactin; Fibrillin; Fn; Fibulins; Gelatins; Ln; Link protein; Osteonectin; Tenascin;

CTGF; FGFR1; CX3CL1; IL1-; IGFBPs; MCP-3/CCL7; TGF-

; TNF-SDF-1/CXCL12

Gelatinase B MMP-9 Aggrecan; Collagens III, IV-V, XI; Decorin; Elastin; Entactin; Fibrillin; Gelatins; Ln; Link protein; Osteonectin; N-telopeptide of collagen I; Vn

MCP-3; CCL11; CCL17; Fractalkine; GRO-alpha;

IGFBP-3; IL1-; IL-2R IL-

8/CXCL8; Kit-L; LIF; TGF-;

TNF- SDF-1/CXCL12; VEGF

Stromelysins

Stromelysin-1 MMP-3 Aggrecan; Collagens III-V, VII, IX- XI; Decorin; Elastin; Entactin; Fibrillin; Fn; Gelatins;Ln; link protein; Osteonectin; Perlecan; Tenascin; Vn;

CTGF; HB-EGF; IL1-; IGFBPs; MCP-1, MCP-2,

MCP-3, MCP-4; IL-1; TGF-

; TNF-SDF-1/CXCL12;

Stromelysin-2 MMP-10 Aggrecan; Collagens III-V; Elastin; Fn; Gelatin; Link protein

Matrilysins

Matrilysin-1 (MMP-7) Aggrecan; Collagens I, IV; Decorin; Elastin; Entactin; Fn; Fibulins; Gelatins; Ln; Link protein; Osteonectin; Osteopontin; Tenascin; Vn; Syndecan-1,

CTGF; Fas-L; HB-EGF; IGFBP-3;

TNF-RANKL

Matrilysin-2 MMP-26 Collagen IV; Fn; Fibrinogen; Gelatin; Vn

www.intechopen.com

Page 16: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

424

Furin-activated MMP

Stromelysin-3 MMP-11 Aggrecan; Fn; Gelatins; Ln; IGFBP-1

Epilysin MMP-28 Unknown

Other secreted-type MMP

Metalloelastase MMP-12 Aggrecan; Collagen I, IV;

Elastin; Entactin; Fibrillin; Fn;

Gelatin; Ln; Osteonectin; Vn;

TNF-

RASI-1 (MMP-19) Aggrecan; Collagen I, IV;

COMP; Fn; Gelatin; Ln;

Tenascin;

IGFBP-3

Enamelysin (MMP-20) Aggrecan; Amelogenin;

COMP; Gelatin;

Unknown

MMP-21 Unknown Unknown

MMP-27 Unknown Unknown

Membrane-anchored MMP

Type I transmembrane-type MMP

MT1-MMP MMP-14 Aggrecan; Collagens I-III, VI;

Entactin; Fibrillin; Fn;

Gelatins; Ln; Osteonectin; Vn;

CTGF; IL-8; MCP-3/CCL7;

TNF-

MT2-MMP MMP-15 Aggrecan; Entactin

MT3-MMP MMP-16 Collagen III; Fn; Gelatins

MT5-MMP MMP-24 PG

GPI-linked MMP

MT4-MMP MMP-17 Gelatin;

MT6-MMP MMP-25 collagen IV; Fibrin; Fn;

Gelatin; Ln

Type II transmembrane-type MMP

Gelatins

MMP-23

CCL11, CC chemokine ligand 11; CCL17, CC chemokine ligand 17, COMP, cartilage oligomeric matrix

protein; CTGF, connective tissue growth factor; Fas-L, Fas ligand; FGF, Fibroblast Growth Factor;, FGFR1,

Fibroblast growth factor receptor 1; Fn, fibronectin; HB-EGF, heparin-binding epidermal growth factor like

growth factor; IGFBP, insulin-like growth factor binding proteins; IL1-, interleukin-1; IL-2RInterleukin

2 receptorL-8, interleukin 8; Kit-L, kit ligand; Ln, laminin; LIF, Leukimia inhibitory factor; LIX-CXL,

lipopolysaccharide induced CXC chemokine, MCP-, monocyte chemotactic protein-; PCPE, Procollagen C

protein enhancer; PG, proteoglycan; Pro, proteinase type; SDF-1/CXCL12, Stromal cell derived factor,

TNF-, tumor necrosis factor-; TGF- transforming growth factor RASI-1, rheumatoid arthritis

synovium inflamed-1; RANKL, receptor activator for nuclear factor B ligand.

Table 1. Validated MMPs substrates that include ECM and non-ECM proteins. Of the long list of non-ECM substrates, only growth factors, receptors and cytokines/chemokines have been extracted because of the role they play in the modification of tissue environment and the modulation of cell functions (Manicone & McGuire, 2008; C. J. Morrison et al., 2009; Shiomi et al., 2010; Sternlicht & Werb, 2001).

www.intechopen.com

Page 17: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

425

TGF- is thought to play a prominent role in the pathogenesis of muscle fibrosis. Its short-

term neutralization by decorin administration resulted in a 40% decline in type I collagen

mRNA expression in mdx mice. In vitro, it stimulates collagen synthesis and inhibits collagen

degradation in fibroblasts (Grande et al., 1997; Ignotz & Massague, 1986; Sharma & Ziyadeh,

1994)}. Myoblast stimulation by TGF-1 induced autocrine production of TGF-1,

downregulation of myogenic proteins, production of fibrosis-related proteins and

phenotypic transformation of myogenic cells to fibrobroblast/myofibroblast cell types in

vitro (Yong Li et al., 2004). TGF-treatment of myogenic cells also upregulated Connective

Tissue Growth Factor (CTGF) (Maeda et al., 2005) incriminated in various fibrotic diseases.

CTGF is overexpressed in dystrophic muscles and is thought to contribute, with TGF-, to

the development of fibrosis (Sun et al., 2008)Interestingly, both factors are validated MMPs

substrates and could be modulated through MMPs action.

Tumor necrosis factor-(TNF-), also upregulated in muscular dystrophy (Porreca et al.,

1999) may exert direct adverse effects on skeletal muscle function and regeneration

potential. Blockade of TNF-by inhibitory antibodies reduced necrosis and contractile

dysfunction in response to eccentric exercise (Piers et al., 2011; Radley et al., 2008). In vitro

TNF- has been shown to stimulate collagen synthesis in fibroblasts (Lurton et al., 1999)

hence contributing directly to muscle fibrosis. In vivo, short-term pharmacological blockade

of TNF- in mdx mice significantly reduced the level of both TGF-1 and type I collagen

mRNA (Gosselin et al., 2004). Whether TNF- mediates muscle fibrosis directly or indirectly

(by upregulating the expression of TGF-1) remains an open question. However, TNF-

induces MMP-9 upregulation in myogenic cells (Torrente et al., 2003).

Concomitance between inflammation and upregulation of MMPs in mouse models or

human diseases with inflammatory conditions, led several groups to propose MMPs as

potential therapeutic targets in pathological conditions with aberrant MMP expression and

activity (reviewed (Clutterbuck et al., 2009)). Inhibition of MMPs has been recently

investigated in mdx mice. MMP-9 inhibition either by the administration of nuclear factor-

kappa B inhibitory peptide, gene deletion or by L-arginine treatment was reported to reduce

muscle injury, inflammation, fibrosis and decrease pro-inflammatory cytokine release (Hnia

et al., 2008; A. Kumar et al., 2010; H. Li et al., 2009). However, whether this inhibition is

acting directly on the development of fibrosis or through prevention of muscle fibers

necrosis and tissue scarring remains an open question.

Extreme precaution has to be taken into consideration regarding MMPs inhibition in muscular

dystrophy particularly as animal models of MMP gain- or loss- of function and clinical trials of

MMP inhibition in cancer patients have unraveled the dual role an individual MMP could

exert, depending on tissue type or stage of the disease (protective/detrimental) (reviewed

(Fanjul-Fernandez et al., 2010). In skeletal muscles, the beneficial effect of certain MMPs has

been documented, underscoring the necessity for better knowledge of the role MMPs are

playing in muscle diseases (Alameddine manuscript in preparation). Indeed, Mmp-2 gene

ablation has been shown to impair the growth of muscle fibers by downregulating VEGF and

nNOS (Miyazaki et al., 2011). Moreover, proteinases upregulation, during satellite cells

activation, is essential for dismantling the satellite cells niche (Pallafacchina et al., 2010) and

MMP-1 has been shown to reduce muscle fibrosis (Kaar et al., 2008).

www.intechopen.com

Page 18: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

426

4.4 MMPs favor cell migration

Myogenic cells have been reported to express various MMPs -MMP-1, -2, -3, -7, -9, -10, -14 and -16, either constitutively or after treatment with growth factors, cytokines or phorbol esters (Balcerzak et al., 2001; Caron et al., 1999; El Fahime et al., 2000; Guérin & Holland, 1995; Kherif et al., 1999; Lewis et al., 2000; Lluri & Jaworski, 2005; Nishimura et al., 2008; Ohtake et al., 2006). Cytokines and growth factors differentially modulate MMPs expression in myogenic cells. Treatment of adult mouse myoblasts by soluble serum fibronectin, PDGF-

BB, TGF- or IGF-1 had no effect on the expression of MMP-9 expression, whereas TNF- and b-FGF reproducibly induced the expression of MMP-9 expression 30- and 10-folds. Other MMPs, such as MMP-1 and MMP-2, were not significantly affected by any of these growth factors (Allen et al., 2003; Torrente et al., 2003).

Fig. 4. Invasion assay establishing the correlation between migratory capacity of myogenic cells and MMP-9 expression levels. Three different cell types, C2C12 and 2 variant clones, expressing different levels of MMP-2 and MMP-9, that were quantified in the same zymography gels with Image J, were assayed in a two chamber migration assay with (+Mat) or without (–Mat) growth factor reduced Matrigel as substrate. The invasive capacity is measured by the ratio between cells that migrated through Matrigel and those diffused through the porous membrane. MMP-2, MMP-9 and total gelatinase values are expressed in arbitrary units. Invasive capacity of C2M9 was > to C2C12>C2F cells.

The role MMPs/TIMPs play in myogenic cells migration and potentially in cell fusion has been confirmed by overexpression and inhibition studies. Myoblasts overexpressing MMP-7 had a higher propensity to form myotubes than parental controls and generated more fibers when transplanted into a single site (Caron et al., 1999). MMP-1 enhanced C2C12 myoblast migration in a wound healing assay in vitro by increasing the expression of migration related

marker proteins such as N-cadherin, -catenin, latent MMP-2 and TIMP-1 (Wang et al., 2009). C2C12 cells stably transfected with MMP-2 and MMP-14 cDNA significantly increased the number of myonuclei without affecting the number of myotubes formed (Echizenya et al.,

www.intechopen.com

Page 19: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

427

2005). MT1-MMP has been proposed as a major MMP checkpoint regulator of myotube formation, as shMT1-MMP partly inhibited muscle cell fusion at a specific stage (Ohtake et al., 2006). MMP-9 and TIMP-1 have also been suspected to play a role in myogenesis in vitro. MMP-9 expression in human myogenic cells favored their migration on fibronectin and its inhibition by a blocking antibody decreased two dimensional cell migration (Lewis et al., 2000). Cells overexpressing MMP-9 have also better three dimensional migratory capacities (Figure 4). They exhibit higher migration when seeded on top of a Matrigel gel that better mimics ECM and their migration is inhibited in the presence of a specific MMP-9 inhibitor (Morgan et al., 2010). Of relevance to this review is that these cells have also higher engraftment capacities. Upon transplantation in a single site in irradiated and non-irradiated muscles of mdx nu/nu mice, they formed more dystrophin positive muscle fibers over larger areas, indicating they migrated better in a dystrophic environment (Morgan et al., 2010).

5. Conclusion

Although promising, there are several challenges to be overcome before stem or precursor cells could be used to treat muscular dystrophies. Apart from reliably and reproducibly identifying and purifying the cells of interest, their characteristics have to be maintained on expansion in culture: attempts at re-creating the niche in vitro may facilitate the retention of stem cell characteristics (Cosgrove et al., 2009; Gilbert et al., 2010). Encouraging results from one laboratory should be independently confirmed, before any particular stem cell is considered for therapeutic application.

Systemic delivery would involve turning a cell into a leukocyte to cross the blood vessel endothelium (Springer, 1994) and then switching on survival, migration, proliferative and myogenic regulatory factors once the cells are within the muscle. Even if it does not prove possible to treat muscles body-wide, transplanting stem cells locally into a small, vital, muscle, e.g. in the finger, may prove more practicable and although not life-saving, would improve the quality of life of DMD patients.

But for successful local as well as systemic delivery of stem cells to skeletal muscle, the

inhospitable muscle environment remains a major hurdle. Studies on the factors and signaling

pathways that hinder donor cell survival, proliferation and migration within both normal and

dystrophic muscle and how these may be modified to augment the regenerative capacity of

transplanted cells, remain vital for the successful use of stem cells in neuromuscular diseases.

More importantly, elucidation of the role MMPs in general and individual MMPs in particular,

play in the modulation of the dystrophic microenvironment and stem cell response to this

environment warrants further study. In light of our present knowledge, it is tempting to

propose that MMPs are temporally upregulated to permit migration and fusion of stem cells,

then down-regulated, after donor-derived muscle has been formed, to reduce inflammation

and fibrosis and thus improve muscle function. However, it is not clear whether the presence

of either stem cells of normal origin, or muscle fibers expressing dystrophin, are sufficient to

prevent the uncontrolled wound healing response that occurs in dystrophic muscles.

6. Acknowledgments

J.E.M is funded by a Wellcome Trust University award, the Muscular Dystrophy Campaign, the Duchenne Parent Project (Netherlands), the International Collaborative Effort for

www.intechopen.com

Page 20: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

428

Duchenne muscular dystrophy, and the Medical Research Council. H.S.A is funded by Association Institut de Myologie/Association Française contre les Myopathies and by INSERM (France).

7. References

Alameddine, H.S.; Dehaupas, M. & Fardeau, M. (1989). Regeneration of skeletal muscle fibers from autologous satellite cells multiplied in vitro. An experimental model for testing cultured cell myogenicity. Muscle Nerve, Vol.12, No.7, (Jul), pp. 544-55, ISSN 0148-639X

Alameddine, H.S.; Hantaï D.; Dehaupas, M.; & Fardeau, M. (1991). Role of persisting basement membrane in the reorganization of myofibres originating from myogenic cell grafts in the rat. Neuromuscular Disorders, Vol.1, No.2, pp. 143-52, ISSN 0960-8966

Alameddine, H.S.; Louboutin,J.P.; Dehaupas, M.; Sebille,A. & Fardeau, M. (1994). Functional recovery induced by satellite cell grafts in irreversibly injured muscles. Cell Transplantation, Vol.3, No.1, (Jan-Feb), pp. 3-14, ISSN 0963-6897

Allen, D.L.; Teitelbaum, D.H. & Kurachi, K. (2003). Growth factor stimulation of matrix metalloproteinase expression and myoblast migration and invasion in vitro. American Journal of Physiology - Cell Physiology, Vol.284, No.4, (Apr 1), pp. C805-C815,

Arechavala-Gomeza, V.; Kinali, M.; Feng, L.; Guglieri, M.; Edge, G.; Main, M.; Hunt, D.; Lehovsky, J.; Straub, V.; Bushby, K.; Sewry, C.A.; Morgan, J.E. & Muntoni, F. (2010). Revertant fibres and dystrophin traces in Duchenne muscular dystrophy: implication for clinical trials. Neuromuscular Disorders, Vol.20, No.5, (May), pp. 295-301, ISSN 1873-2364

Balcerzak, D.; Querengesser, L.; Dixon, W.T. & Baracos, V.E. (2001). Coordinated expression of matrix-degrading proteinases and their activators and inhibitors in bovine skeletal muscle. Journal Animal Sciences, Vol.79, No.1, (Jan 1), pp. 94-107,

Bani, C.; Lagrota-Candido, J.; Pinheiro, D.F.; Leite, P.E.; Salimena, M.C.; Henriques-Pons, A. & Quirico-Santos, T. (2008). Pattern of metalloprotease activity and myofiber regeneration in skeletal muscles of mdx mice. Muscle Nerve, Vol.37, No.5, (May), pp. 583-92, ISSN 0148-639X

Banks, G.B. & Chamberlain, J.S. (2008). The value of mammalian models for Duchenne muscular dystrophy in developing therapeutic strategies. Current Topics in Developmental Biology, Vol.84, pp. 431-53,

Barnes, B.R.; Szelenyi,E.R.; Warren, G.L. & Urso, M.L. (2009). Alterations in mRNA and protein levels of metalloproteinases-2, -9, and -14 and tissue inhibitor of metalloproteinase-2 responses to traumatic skeletal muscle injury. American Journal of Physiology – Cell Physiology, Vol.297, No.6, (Dec), pp. C1501-8, ISSN 1522-1563

Beauchamp, J.R.; Morgan, J.E.; Pagel, C.N. & Partridge, T.A. (1999). Dynamics of myoblast transplantation reveal a discrete minority of precursors with stem cell-like properties as the myogenic source. The Journal of Cell Biology, Vol.144, No.6, (Mar 22), pp. 1113-22,

Bekaert, S.; De Meyer, T. & Van Oostveldt, P. (2005). Telomere attrition as ageing biomarker. Anticancer Research, Vol.25, No.4, (Jul-Aug), pp. 3011-21, ISSN 0250-7005

www.intechopen.com

Page 21: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

429

Benchaouir, R.; Meregalli, M.; Farini ,A.; D'Antona, G.; Belicchi, M.; Goyenvalle, A.; Battistelli, M.; Bresolin, N.; Bottinelli, R.; Garcia, L. & Torrente, Y. (2007). Restoration of human dystrophin following transplantation of exon-skipping-engineered DMD patient stem cells into dystrophic mice. Cell Stem Cell, Vol.1, No.6, (Dec 13), pp. 646-57,

Bernasconi, P.; Di Blasi, C.; Mora, M.; Morandi, L.; Galbiati, S.; Confalonieri, P.; Cornelio, F.& Mantegazza, R. (1999). Transforming growth factor-[beta]1 and fibrosis in congenital muscular dystrophies. Neuromuscular Disorders, Vol.9, No.1, (Jan 1), pp. 28-33,

Berthon, P.; Duguez, S.; Favier, F.B.; Amirouche, A.; Feasson, L.; Vico, L.; Denis, C. & Freyssenet, D. (2007). Regulation of ubiquitin-proteasome system, caspase enzyme activities, and extracellular proteinases in rat soleus muscle in response to unloading. Pflügers Archives, Vol.454, No.4, (Jul), pp. 625-33, ISSN 0031-6768

Blau, H.M.; Webster, C. & Pavlath, G.K. (1983). Defective myoblasts identified in Duchenne muscular dystrophy. Proceedings of the National Academy of Science USA, Vol.80, No.15, (Aug), pp. 4856-60, ISSN 0027-8424

Blaveri, K.; Heslop, L.; Yu, D.S.; Rosenblatt, J.D.; Gross, J.G.; Partridge, T.A. & Morgan, J.E. (1999). Patterns of repair of dystrophic mouse muscle: studies on isolated fibers. Developmental Dynamics, Vol.216, No.3, pp. 244-56., ISSN

Bockhold, K.J.; Rosenblatt J.D. & Partridge, T.A. (1998). Aging normal and dystrophic mouse muscle: analysis of myogenicity in cultures of living single fibers. Muscle Nerve, Vol.21, No.2, (Feb), pp. 173-83,

Bokhoven, M.; Stephen, S.L.; Knight, S.; Gevers, E.F.; Robinson, I.C.; Takeuchi, Y. & Collins, M.K. (2009). Insertional gene activation by lentiviral and gammaretroviral vectors. Journal of Virology, Vol.83, No.1, (Jan), pp. 283-94,

Boldrin, L.; Muntoni, F. & Morgan, J.E. (2010). Are human and mouse satellite cells really the same? Journal of Histochemistry & Cytochemistry, Vol.58, No.11, (Nov), pp. 941-55, ISSN 1551-5044

Boldrin, L.; Zammit, P.S.; Muntoni, F. & Morgan, J.E. (2009). Mature adult dystrophic mouse muscle environment does not impede efficient engrafted satellite cell regeneration and self-renewal. Stem Cells, Vol.27, No.10, pp. 2478-2487, ISSN 1549-4918

Bourboulia, D. & Stetler-Stevenson, W.G. (2010). Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs): Positive and negative regulators in tumor cell adhesion. Seminars in Cancer Biology, Vol.15, No.11, (Nov), pp. 1109-24,

Brimah, K.; Ehrhardt, J.; Mouly, V.; Butler-Browne, G.S.; Partridge, T.A. & Morgan, J.E. (2004). Human muscle precursor cell regeneration in the mouse host is enhanced by growth factors. Human Gene Therapy, Vol.15, No.11, (Nov), pp. 1109-24,

Bulfield, G.; Siller, W.G.; Wight, P.A. & Moore, K.J. (1984). X chromosome-linked muscular dystrophy (mdx) in the mouse. Proceedings of the National Academy of Science USA,Vol.81, No.4, (Feb), pp. 1189-92,

Bushby, K.; Finkel, R.; Birnkrant, D.J.; Case, L.E.; Clemens, P.R.; Cripe, L.; Kaul, A.; Kinnett, K.; McDonald, C.; Pandya, S.; Poysky, J.; Shapiro, F.; Tomezsko, J. & Constantin, C. (2010). Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and pharmacological and psychosocial management. Lancet Neurology, Vol.9, No.1, (Jan), pp. 77-93, ISSN 1474-4465

www.intechopen.com

Page 22: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

430

Caron, N.J.; Asselin, I.; Morel, G. & Tremblay, J.P. (1999). Increased myogenic potential and fusion of matrilysin-expressing myoblasts transplanted in mice. Cell Transplantation, Vol.8, No.5, (Sep-Oct), pp. 465-76, ISSN 0963-6897

Chan, J.; O'Donoghue, K.; Gavina, M.; Torrente, Y.; Kennea, N.; Mehmet, H.; Stewart, H.; Watt ,D.J.; Morgan, J.E. & Fisk, N.M. (2006). Galectin-1 induces skeletal muscle differentiation in human fetal mesenchymal stem cells and increases muscle regeneration. Stem Cells, Vol.24, No.8, (Aug), pp. 1879-91,

Chen, Y.W.; Zhao, P.; Borup, R. & Hoffman, E. (2000). Expression profiling in the muscular dystrophies: identification of novel aspects of molecular pathophysiology. The Journal of Cell Biology, Vol.151, pp. 1321–36,

Chen, Y.W.; Nagaraju, K.; Bakay, M.; McIntyre, O.; Rawat, R.; Shi, R. & Hoffman, E.P. (2005). Early onset of inflammation and later involvement of TGF{beta} in Duchenne muscular dystrophy. Neurology, Vol.65, No.6, (Sep 27), pp. 826-834,

Ciuffi, A. (2008). Mechanisms governing lentivirus integration site selection. Current Gene Therapy, Vol.8, No.6, (Dec), pp. 419-29,

Clutterbuck, A.L.; Asplin, K.E.; Harris, P.; Allaway, D. & Mobasheri, A. (2009). Targeting matrix metalloproteinases in inflammatory conditions. Current Drug Targets, Vol.10, No.12, (Dec), pp. 1245-54, ISSN 1873-5592

Collins, C.A. & Morgan, J.E. (2003). Duchenne's muscular dystrophy: animal models used to investigate pathogenesis and develop therapeutic strategies. International Journal of Experimental Pathology, Vol.84, No.4, (Aug), pp. 165-72,

Collins, C.A.; Olsen, I.; Zammit, P.S.; Heslop, L.; Petrie, A.; Partridge T.A. & Morgan,. J.E. (2005). Stem cell function, self-renewal, and behavioral heterogeneity of cells from the adult muscle satellite cell niche. Cell, Vol.122, No.2, pp. 289-301,

Cooper, R.N.; Irintchev, A.; Di Santo, J.P.; Zweyer, M.; Morgan, J.E.; Partridge, T.A.; Butler-Browne, G.S.; Mouly, V. & Wernig, A. (2001). A new immunodeficient mouse model for human myoblast transplantation. Human Gene Therapy, Vol.12, No.7, (May 1), pp. 823-31,

Cosgrove, B.D.; Sacco, A.; Gilbert, P.M. & Blau, H.M. (2009). A home away from home: challenges and opportunities in engineering in vitro muscle satellite cell niches. Differentiation, Vol.78, No.2-3, (Sep-Oct), pp. 185-94, ISSN 1432-0436

Cousins, J.C.; Woodward, K.J.; Gross, J.G.; Partridge, T.A. & Morgan, J.E. (2004). Regeneration of skeletal muscle from transplanted immortalised myoblasts is oligoclonal. Journal of Cell Science, Vol.117, No.15, (Jul 1), pp. 3259-3269,

Decary, S.; Mouly, V. & Butler-Browne, G.S. (1996). Telomere length as a tool to monitor satellite cell amplification for cell-mediated gene therapy. Human Gene Therapy, Vol.7, No.11, (Jul 10), pp. 1347-50,

Decary, S.; Mouly, V.; Hamida, C.B.; Sautet, A.; Barbet, J.P. & Butler-Browne, G.S. (1997). Replicative potential and telomere length in human skeletal muscle: implications for satellite cell-mediated gene therapy. Human Gene Therapy, Vol.8, No.12, (Aug 10), pp. 1429-38,

Dehne, N.; Kerkweg, U.; Flohe, S.B.; Brune, B. & Fandrey, J. (2011). Activation of HIF-1 in skeletal muscle cells after exposure to damaged muscle cell debris. Shock, Vol. 35, No.6, (Jun), pp. 632-8., ISSN 1073-2322

Dellavalle, A.; Sampaolesi, M.; Tonlorenzi, R.; Tagliafico, E.; Sacchetti, B.; Perani, L.; Innocenzi, A.; Galvez, B.G.; Messina, G.; Morosetti, R.; Li, S.; Belicchi, M.; Peretti,

www.intechopen.com

Page 23: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

431

G.; Chamberlain, J.S.; Wright, W.E.; Torrente, Y.; Ferrari, S.; Bianco P. & Cossu, G. (2007). Pericytes of human skeletal muscle are myogenic precursors distinct from satellite cells. Nature Cell Biology, Vol.9, No.3, (Mar), pp. 255-67,

Demoule, A.; Divangahi, M.; Danialou, G.; Gvozdic, D.; Larkin, G.; Bao; W.& Petrof, B.J. (2005). Expression and regulation of CC class chemokines in the dystrophic (mdx) diaphragm. American Journal of Respiratory Cell and Molecular Biology, Vol.33, No.2, (Aug), pp. 178-185,

Diaz-Manera, J.; Touvier, T.; Dellavalle, A.; Tonlorenzi, R.; Tedesco, F.S.; Messina, G.; Meregalli, M.; Navarro, C.; Perani, L.; Bonfanti, C.; Illa, I.; Torrente, Y.& Cossu, G. (2010). Partial dysferlin reconstitution by adult murine mesoangioblasts is sufficient for full functional recovery in a murine model of dysferlinopathy. Cell death & disease, Vol.1, pp. e61, ISSN 2041-4889

Echizenya, M.; Kondo, S.; Takahashi, R.; Oh, J.; Kawashima, S.; Kitayama, H.; Takahashi, C. & Noda, M. (2005). The membrane-anchored MMP-regulator RECK is a target of myogenic regulatory factors. Oncogene, Vol.24, No.38, pp. 5850-5857,

Ehrhardt, J.; Brimah, K.; Adkin, C.; Partridge, T. & Morgan, J. (2007). Human muscle precursor cells give rise to functional satellite cells in vivo. Neuromuscular Disorders, Vol.17, No.8, (Aug), pp. 631-8,

El Fahime, E.; Torrente, Y.; Caron, N.J.; Bresolin, M.D. & Tremblay, J.P. (2000). In vivo migration of transplanted myoblasts requires Matrix Metalloproteinase activity. Experimental Cell Research, Vol.258, No.2, (Aug), pp. 279-287,

Emery, A.E. (2002). The muscular dystrophies. Lancet, Vol.359, No.9307, (Feb 23), pp. 687-95, ISSN 0140-6736

Fadic, R.; Mezzano, V.; Alvarez, K.; Cabrera, D.; Holmgren, J. & Brandan, E. (2006). Increase in decorin and biglycan in Duchenne Muscular Dystrophy: role of fibroblasts as cell source of these proteoglycans in the disease. Journal of Cellular and molecular medicine, Vol.10, No.3, (Jul-Sep), pp. 758-69, ISSN 1582-1838

Fanjul-Fernandez, M.; Folgueras, A.R.; Cabrera, S. & Lopez-Otin, C. (2010). Matrix metalloproteinases: evolution, gene regulation and functional analysis in mouse models. Biochimica Biophysica Acta,Vol.1803, No.1, (Jan), pp. 3-19, ISSN 0006-3002

Ferrari, G.; Cusella-De Angelis, G.; Coletta, M.; Paolucci, E.; Stornaiuolo, A.; Cossu, G. & Mavilio, F. (1998). Muscle regeneration by bone marrow-derived myogenic progenitors. Science, Vol.279, No.5356, (Mar 6), pp. 1528-30,

Ferre, P.J.; Liaubet, L.; Concordet, D.; SanCristobal, M.; Uro-Coste, E.; Tosser-Klopp, G.; Bonnet, A.; Toutain, P.L.; Hatey, F. & Lefebvre, H.P. (2007). Longitudinal analysis of gene expression in porcine skeletal muscle after post-injection local injury. Pharmaceutical Research, Vol.24, No.8, (Aug), pp. 1480-9, ISSN 0724-8741

Frisdal, E.; Teiger, E.; Lefaucheur, J.P.; Adnot, S.; Planus, E.; Lafuma, C.& D'Ortho, M. P.. (2000). Increased expression of gelatinases and alteration of basement membrane in rat soleus muscle following femoral artery ligation. Neuropathology and Applied Neurobiology, Vol.26, No.1, (Feb), pp. 11-21, ISSN 0305-1846

Fukushima, K.; Nakamura, A.; Ueda, H.; Yuasa, K.; Yoshida, K.; Takeda, S. & Ikeda, S. (2007). Activation and localization of matrix metalloproteinase-2 and -9 in the skeletal muscle of the muscular dystrophy dog (CXMDJ). BMC Musculoskeletal Disorders, Vol.8, pp. 54, ISSN 1471-2474

www.intechopen.com

Page 24: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

432

Galvez, B.G.; Sampaolesi, M.; Brunelli, S.; Covarello, D.; Gavina, M.; Rossi, B.; Constantin, G.; Torrente, Y. & Cossu, G. (2006). Complete repair of dystrophic skeletal muscle by mesoangioblasts with enhanced migration ability. The Journal of Cell Biology, Vol.174, No.2, (Jul 17), pp. 231-43,

Gerard, C.; Forest, M.A.; Beauregard, G.; Skuk, D. & Tremblay, J.P.. (2011). Fibrin gel improves the survival of transplanted myoblasts. Cell Transplantation, Vol.20, No.5, (Apr 29), pp. ISSN 1555-3892

Giannelli, G.; De Marzo, A.; Marinosci, F. & Antonaci, S. (2005). Matrix metalloproteinase imbalance in muscle disuse atrophy. Histology & Histopathology, Vol.20, No.1, (Jan), pp. 99-106, ISSN 0213-3911

Gilbert, P.M.; Havenstrite, K.L.; Magnusson, K.E.; Sacco, A.; Leonardi, N.A.; Kraft, P.; Nguyen, N.K.; Thrun, S.; Lutolf, M.P. & Blau, H.M. (2010). Substrate elasticity regulates skeletal muscle stem cell self-renewal in culture. Science, Vol.329, No.5995, (Aug 27), pp. 1078-81, ISSN 1095-9203

Gosselin, L.E.; Williams, J.E.; Deering, M.; Brazeau, D.; Koury, S. & Martinez, D.A. (2004).

Localization and early time course of TGF- mRNA expression in dystrophic muscle. Muscle Nerve, Vol.30, No.5, pp. 645-653, ISSN 1097-4598

Goyenvalle, A. & Davies, K.E. (2011). Challenges to oligonucleotides-based therapeutics for Duchenne muscular dystrophy. Skeletal muscle, Vol.1, No.1, pp. 8, ISSN 2044-5040

Grande, J.P.; Melder, D.C. & Zinsmeister, A.R. (1997). Modulation of collagen gene expression by cytokines: stimulatory effect of transforming growth factor-beta1, with divergent effects of epidermal growth factor and tumor necrosis factor-alpha on collagen type I and collagen type IV. Journal of Laboratory and Clinical Medicine, Vol.130, pp. 476–486.,

Gross, J.G. & Morgan, J.E. (1999). Muscle precursor cells injected into irradiated mdx mouse muscle persist after serial injury. Muscle Nerve, Vol.22, No.2, pp. 174-85.,

Guérin, C.W. & Holland, P.C. (1995). Synthesis and secretion of matrix-degrading metalloproteases by human skeletal muscle satellite cells. Developmental Dynamics, Vol.202, No.1, (Jan), pp. 91-99,

Guglieri, M. & Bushby, K. (2010). Molecular treatments in Duchenne muscular dystrophy. Current Opinion in Pharmacology, Vol.10, No.3, (Jun), pp. 331-7, ISSN 1471-4973

Hemmann, S.; Graf, J.; Roderfeld, M. & Roeb, E. (2007). Expression of MMPs and TIMPs in liver fibrosis - a systematic review with special emphasis on anti-fibrotic strategies. Journal of Hepatology, Vol.46, No.5, pp. 955-975,

Heslop, L.; Morgan, J.E. & Partridge, T.A. (2000). Evidence for a myogenic stem cell that is exhausted in dystrophic muscle. Journal of Cell Science, Vol.113 (Pt 12), (Jun), pp. 2299-308,

Hirata, A.; Masuda, S.; Tamura, T.; Kai, K.; Ojima, K.; Fukase, A.; Motoyoshi, K.; Kamakura, K.; Miyagoe-Suzuki, Y. & Takeda, S. (2003). Expression profiling of cytokines and related genes in regenerating skeletal muscle after cardiotoxin injection: a role for osteopontin. American Journal of Pathology, Vol.163, pp. 203–15,

Hnia, K.; Gayraud, J.; Hugon, G.; Ramonatxo, M.; De La Porte, S.; Matecki, S.& Mornet, D. (2008). L-arginine decreases inflammation and modulates the nuclear factor-kappaB/matrix metalloproteinase cascade in mdx muscle fibers. American Journal of Pathology, Vol.172, No.6, (Jun), pp. 1509-19, ISSN 1525-2191

www.intechopen.com

Page 25: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

433

Hoffman, E.P.; Morgan, J.E.; Watkins, S.C. & Partridge, T.A. (1990). Somatic reversion/suppression of the mouse mdx phenotype in vivo. Journal of the Neurological Sciences , Vol.99, No.1, (Oct), pp. 9-25,

Hoffman, E.P.; Bronson, A.; Levin, A.A.; Takeda, S.; Yokota, T.;. Baudy, A.R & Connor, E.M. (2011). Restoring dystrophin expression in duchenne muscular dystrophy muscle progress in exon skipping and stop codon read through. American Journal of Pathology, Vol.179, No.1, (Jul), pp. 12-22, ISSN 1525-2191

Holmbeck, K.; Bianco, P.; Pidoux, I.; Inoue, S.; Billinghurst, R.C.; Wu, W.; Chrysovergis, K.; Yamada, S.; Birkedal-Hansen, H.& Poole, A.R. (2005). The metalloproteinase MT1-MMP is required for normal development and maintenance of osteocyte processes in bone. Journal of Cell Science, Vol.118, No.Pt 1, (Jan 1), pp. 147-56, ISSN 0021-9533

Hulboy, D.L.; Rudolph, L.A. & Matrisian, L.M. (1997). Matrix metalloproteinases as mediators of reproductive function. Molecular Human Reproduction, Vol.3, No.1, (Jan), pp. 27-45, ISSN 1360-9947

Ignotz, R.A. & Massague, J. (1986). Transforming growth factor-beta stimulates the expression of fibronectin and collagen and their incorporation into the extracellular matrix. Journal of Biological Chemistry, Vol.261, pp. 4337–4345.,

Irintchev, A.; Langer, M.; Zweyer, M.; Theisen R. & Wernig, A. (1997). Functional improvement of damaged adult mouse muscle by implantation of primary myoblasts. Journal of Physiology, Vol.500 (Pt 3), (May 1), pp. 775-85,

Jackson, K.A.; Snyder, D.S. & Goodell, M.A. (2004). Skeletal muscle fiber-specific green autofluorescence: potential for stem cell engraftment artifacts. Stem Cells, Vol.22, No.2, pp. 180-7, ISSN 1066-5099

Kaar, J.L.; Li, Y.; Blair, H.C.; Asche, G.; Koepsel, R.R.; Huard, J. & Russell, A.J. (2008). Matrix metalloproteinase-1 treatment of muscle fibrosis. Acta Biomaterialia, Vol.4, No.5, (Sep), pp. 1411-20, ISSN 1742-7061

Kherif, S.; Lafuma, C.; Dehaupas, M.; Lachkar, S.; Fournier, J.G.; Verdiere-Sahuque, M.; Fardeau, M. & Alameddine, H.S. (1999). Expression of matrix metalloproteinases 2 and 9 in regenerating skeletal muscle: a study in experimentally injured and mdx muscles. Developmental Biology, Vol.205, No.1, (Jan 1), pp. 158-70, ISSN 0012-1606

Kinoshita, I.; Huard J. & Tremblay, J.P. (1994a). Utilization of myoblasts from transgenic mice to evaluate the efficacy of myoblast transplantation. Muscle Nerve, Vol.17, No.9, (Sep), pp. 975-80, ISSN 0148-639X

Kinoshita, I.; Vilquin, J.T.; Guerette, B.; Asselin, I.; Roy, R.; Lille S. & Tremblay, J.P. (1994b). Immunosuppression with FK 506 insures good success of myoblast transplantation in mdx mice. Transplantation Proceedings, Vol.26, No.6, (Dec), pp. 3518, ISSN 0041-1345

Kumar, A.; Bhatnagar, S. & Kumar, A. (2010). Matrix metalloproteinase inhibitor batimastat alleviates pathology and improves skeletal muscle function in dystrophin-deficient mdx mice. American Journal of Pathology, Vol.177, No.1, (Jul), pp. 248-60, ISSN 1525-2191

Kumar, M.; Keller, B.; Makalou, N. & Sutton, R.E. (2001). Systematic determination of the packaging limit of lentiviral vectors. Human Gene Therapy, Vol.12, No.15, (Oct 10), pp. 1893-905,

Lai, Y.; Thomas, G.D.; Yue, Y.; Yang, H.T.; Li, D.; Long, C.; Judge, L.; Bostick, B.; Chamberlain, J.S.; Terjung, R.L. & Duan, D. (2009). Dystrophins carrying spectrin-

www.intechopen.com

Page 26: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

434

like repeats 16 and 17 anchor nNOS to the sarcolemma and enhance exercise performance in a mouse model of muscular dystrophy. The Journal of Clinical Investigation, Vol.119, No.3, (Mar), pp. 624-35,

Lefaucheur, J.P. & Sebille, A. (1995). Basic fibroblast growth factor promotes in vivo muscle regeneration in murine muscular dystrophy. Neuroscience Letters, Vol.202, No.1-2, (Dec 29), pp. 121-4,

Lewis, M.P.; Tippett, H.L.; Sinanan, A.C.; Morgan, M.J. & Hunt, N.P. (2000). Gelatinase-B (matrix metalloproteinase-9; MMP-9) secretion is involved in the migratory phase of human and murine muscle cell cultures. Journal of Muscle Research and Cell Motility, Vol.21, No.3, pp. 223-233,

Li, H.; Mittal, A.; Makonchuk, D.Y.; Bhatnagar, S. & Kumar, A. (2009). Matrix metalloproteinase-9 inhibition ameliorates pathogenesis and improves skeletal muscle regeneration in muscular dystrophy. Human Molecular Genetics, Vol.18, No.14, (Jul 15), pp. 2584-98, ISSN 1460-2083

Li, S.; Kimura, E.; Fall, B.M.; Reyes, M.; Angello, J.C.; Welikson, R.; Hauschka, S.D. & Chamberlain, J.S. (2005). Stable transduction of myogenic cells with lentiviral vectors expressing a minidystrophin. Gene Therapy , Vol.12, No.14, (Jul), pp. 1099-108,

Li, Y.; Foster, W.; Deasy, B.M.; Chan, Y.; Prisk, V.; Tang ,Y.; Cummins, J. & Huard, J. (2004). Transforming Growth Factor-{beta}1 induces the differentiation of myogenic cells into fibrotic cells in injured skeletal muscle: A key event in muscle fibrogenesis. American Journal of Pathology, Vol.164, No.3, (March 1, 2004), pp. 1007-1019,

Liu, X.; Lee, D.J.; Skittone, L.K.; Natsuhara, K. & Kim, H.T. (2010). Role of gelatinases in disuse-induced skeletal muscle atrophy. Muscle Nerve, Vol.41, No.2, (Feb), pp. 174-8, ISSN 1097-4598

Lluri, G. & Jaworski, D.M. (2005). Regulation of TIMP-2, MT1-MMP, and MMP-2 expression during C2C12 differentiation. Muscle Nerve, Vol.32, No.4, (Oct), pp. 492-9, ISSN 0148-639X

Lurton, J.; Soto, H.; Narayanan, A. & Raghu, G. (1999). Regulation of human lung fibroblast C1q-receptors by transforming growth factor-beta and tumor necrosis factor-alpha. Experimental Lung Research, Vol.25, pp. 151–164,

Maeda, N.; Kanda, F.; Okuda, S.; Ishihara, H. & Chihara, K. (2005). Transforming growth factor-beta enhances connective tissue growth factor expression in L6 rat skeletal myotubes. Neuromuscular Disorders, Vol.15, No.11, (Nov), pp. 790-3,

Manicone, A.M. & McGuire, J.K. (2008). Matrix metalloproteinases as modulators of inflammation. Seminars of Cell and Developmental Biology, Vol.19, No.1, (Feb), pp. 34-41, ISSN 1084-9521

Mather, K.A.; Jorm, A.F.; Parslow, R.A. & Christensen, H. (2011). Is telomere length a biomarker of aging? A review. The Journals of Gerontology. Series A, Biological sciences and medical sciences, Vol.66, No.2, (Feb), pp. 202-13, ISSN 1758-535X

Mauro, A. (1961). Satellite cell of skeletal muscle fibers. Journal of Biophysical and Biochemical Cytology, Vol.9, (Feb), pp. 493-5, ISSN 0095-9901

Meng, J.; Muntoni, F.& Morgan, J.E. (2011a). Stem cells to treat muscular dystrophies - where are we? Neuromuscular Disorders, Vol.21, No.1, (Jan), pp. 4-12, ISSN 1873-2364

www.intechopen.com

Page 27: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

435

Meng, J.; Adkin, C.F.; Xu, S.W.; Muntoni, F. & Morgan, J.E. (2011b). Contribution of human muscle-derived cells to skeletal muscle regeneration in dystrophic host mice. PloS One, Vol.6, No.3, pp. e17454, ISSN 1932-6203

Meng, J.; Adkin, C.F.; Arechavala-Gomeza, V.; Boldrin, L.; Muntoni, F. & Morgan, J.E. (2010). The contribution of human synovial stem cells to skeletal muscle regeneration. Neuromuscular Disorders, Vol.20, No.1, (Jan), pp. 6-15, ISSN 1873-2364

Meregalli, M.; Farini, A. & Torrente, Y. (2008). Combining stem cells and exon skipping strategy to treat muscular dystrophy. Expert Opinion in Biological Therapy, Vol.8, No.8, (Aug), pp. 1051-61,

Miyazaki, D.; Nakamura, A.; Fukushima, K.; Yoshida, K.; Takeda, S. & Ikeda, S.I. (2011). Matrix metalloproteinase-2 ablation in dystrophin-deficient mdx muscles reduces angiogenesis resulting in impaired growth of regenerated muscle fibers. Human Molecular Genetics, Vol.20, No.9, (May 1), pp. 1787-99., ISSN 1460-2083

Monaco, A.P.; Bertelson, C.J.; Middlesworth, W.; Colletti, C.A.; Aldridge, J.; Fischbeck, K.H.; Bartlett, R.; Pericak-Vance, M.A.; Roses, A.D. & Kunkel, L.M. (1985). Detection of deletions spanning the Duchenne muscular dystrophy locus using a tightly linked DNA segment. Nature, Vol.316, No.6031, (Aug 29-Sep 4), pp. 842-5, ISSN 0028-0836

Montini, E.; Cesana, D.; Schmidt, M.; Sanvito, F.; Ponzoni, M.; Bartholomae, C.; Sergi Sergi, L.; Benedicenti, F.; Ambrosi, A.; Di Serio, C.; Doglioni, C.; von Kalle, C. & Naldini, L. (2006). Hematopoietic stem cell gene transfer in a tumor-prone mouse model uncovers low genotoxicity of lentiviral vector integration. Nature Biotechnology, Vol.24, No.6, (Jun), pp. 687-96,

Morgan, J.; Rouche, A.; Bausero, P.; Houssaini, A.; Gross, J.; Fiszman, M.Y. & Alameddine,H.S. (2010). MMP-9 overexpression improves myogenic cell migration and engraftment. Muscle Nerve, Vol.42, No.4, (Oct), pp. 584-95, ISSN 1097-4598

Morgan, J.E. & P.S. Zammit. (2010). Direct effects of the pathogenic mutation on satellite cell function in muscular dystrophy. Experimental Cell Research, Vol.316, No.18, pp. 3100-3108, ISSN 1090-2422

Morgan, J.E.; Hoffman, E.P. & Partridge, T.A. (1990). Normal myogenic cells from newborn mice restore normal histology to degenerating muscles of the mdx mouse. The Journal of Cell Biology, Vol.111, No.6 Pt 1, pp. 2437-49.,

Morgan, J.E.; Gross, J.G.; Pagel, C.N.; Beauchamp, J.R.; Fassati, A.; Thrasher, A.J.; Di Santo, J.P.; Fisher, I.B.; Shiwen, X.; Abraham, D.J.& Partridge,T.A. (2002). Myogenic cell proliferation and generation of a reversible tumorigenic phenotype are triggered by preirradiation of the recipient site. The Journal of Cell Biology, Vol.157, No.4, pp. 693-702, ISSN 0021-9525

Morrison, C.J.; Butler, G.S.; Rodriguez, D. & Overall, C.M. (2009). Matrix metalloproteinase proteomics: substrates, targets, and therapy. Current Opinion in Cell Biology, Vol.21, No.5, (Oct), pp. 645-53, ISSN 1879-0410

Morrison, J.; Lu, Q.L.; Pastoret, C.; Partridge T. & Bou-Gharios, G. (2000). T-cell-dependent fibrosis in the mdx dystrophic mouse. Laboratory Investigation, Vol.80, No.6, pp. 881-91.,

Murphy, G. (2010). Fell-Muir Lecture: Metalloproteinases: from demolition squad to master regulators. International Journal of Experimental Pathology, Vol.91, No.4, (Aug), pp. 303-13, ISSN 1365-2613

www.intechopen.com

Page 28: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

436

Nakamura, A. & Takeda, S. (2011). Mammalian models of Duchenne Muscular Dystrophy: pathological characteristics and therapeutic applications. Journal of Biomedicine & Biotechnology,Vol.2011, pp. 184393, ISSN 1110-7251

Negroni, E.; Vallese, D.; Vilquin, J.T.; Butler-Browne, G.; Mouly, V. & Trollet, C. (2011). Current advances in cell therapy strategies for muscular dystrophies. Expert Opinion on Biological Therapy, Vol.11, No.2, (Feb), pp. 157-76, ISSN 1744-7682

Negroni, E.; Riederer, I.; Chaouch, S.; Belicchi, M.; Razini, P.; Di Santo, J.; Torrente, Y.; Butler-Browne, G.S. & Mouly, V. (2009). In vivo myogenic potential of human CD133+ muscle-derived stem cells: a quantitative study. Molecular Therapy, Vol.17, No.10, (Oct), pp. 1771-8, ISSN 1525-0024

Niebroj-Dobosz, I.; Madej-Pilarczyk, A.; Marchel, M.; Sokolowska, B. & Hausmanowa-Petrusewicz, I. (2009). Matrix metalloproteinases in serum of Emery-Dreifuss muscular dystrophy patients. Acta Biochimica Polonica, Vol.56, No.4, pp. 717-22, ISSN 1734-154X

Nishimura, T.; Nakamura, K.; Kishioka, Y.; Kato-Mori, Y.; Wakamatsu, J. & Hattori, A. (2008). Inhibition of matrix metalloproteinases suppresses the migration of skeletal muscle cells. Journal of Muscle Research and Cell Motility, Vol.29, No.1, pp. 37-44, ISSN 0142-4319

Ohtake, Y.; Tojo, H. & Seiki, M. (2006). Multifunctional roles of MT1-MMP in myofiber formation and morphostatic maintenance of skeletal muscle. Journal of Cell Science, Vol.119, No Pt 18, (Sep 15), pp. 3822-32, ISSN 0021-9533

Pagel, C.N. & Partridge, T.A. (1999). Covert persistence of mdx mouse myopathy is revealed by acute and chronic effects of irradiation. Journal of Neurological Science, Vol.164, No.2, (Apr 1), pp. 103-16,

Pallafacchina, G.; Francois, S.; Regnault, B.; Czarny, B.; Dive, V.; Cumano, A.; Montarras, D. & Buckingham, M. (2010). An adult tissue-specific stem cell in its niche: a gene profiling analysis of in vivo quiescent and activated muscle satellite cells. Stem Cell Research, Vol.4, No.2, (Mar), pp. 77-91, ISSN 1876-7753

Palmieri, B.; Tremblay, J.P. & Daniele, L. (2010). Past, present and future of myoblast transplantation in the treatment of Duchenne muscular dystrophy. Pediatric transplantation, Vol.14, No.7, (Nov), pp. 813-9, ISSN 1399-3046

Palumbo, R.; Sampaolesi, M.; De Marchis, F.; Tonlorenzi, R.; Colombetti, S.; Mondino, A.; Cossu G. & Bianchi, M.E. (2004). Extracellular HMGB1, a signal of tissue damage, induces mesoangioblast migration and proliferation. The Journal of Cell Biology, Vol.164, No.3, (Feb 2), pp. 441-9, ISSN 0021-9525

Partridge, T.A.; Morgan, J.E.; Coulton, G.R.; Hoffman, E.P. & Kunkel, L.M. (1989). Conversion of mdx myofibers from dystrophin-negative to-positive by injection of normal myoblasts. Nature, Vol.337, pp. 176-179,

Pellegrini, K.L. & Beilharz, M.W. (2011). The survival of myoblasts after intramuscular transplantation is improved when fewer cells are injected. Transplantation, Vol.91, No.5, (Mar 15), pp. 522-6, ISSN 1534-6080

Piers, A.T.; Lavin, T.; Radley-Crabb, H.G.; Bakker, A.J.; Grounds ,M.D. & Pinniger, G.J. (2011). Blockade of TNF in vivo using cV1q antibody reduces contractile dysfunction of skeletal muscle in response to eccentric exercise in dystrophic mdx and normal mice. Neuromuscular Disorders, Vol.21, No.2, (Feb), pp. 132-41, ISSN 1873-2364

www.intechopen.com

Page 29: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

437

Pisani, D.F.; Clement, N.; Loubat, A.; Plaisant, M.; Sacconi, S.; Kurzenne, J.Y.; Desnuelle, C.; Dani C. &Dechesne, C.A. (2010). Hierarchization of myogenic and adipogenic progenitors within human skeletal muscle. Stem Cells, Vol.28, No.12, (Dec), pp. 2182-94, ISSN 1549-4918

Porreca, E.; Guglielmi, M.; Uncini, A.; Di Gregorio, P.; Angelini, A.; Di Febbo, C.; Pierdomenico, S.; Baccante G. & Cuccurullo,. F. (1999). Haemostatic abnormalities, cardiac involvement and serum tumor necrosis factor levels in X-linked dystrophic patients. Thrombosis Haemostasis, Vol.81, pp. 543–546.,

Porter, J.D.; Guo, W.; Merriam, A.P.; Khanna, S.; Cheng, G.; Zhou, X.; Andrade, F.H.; Richmonds, C. & Kaminski, H.J. (2003). Persistent over-expression of specific CC class chemokines correlates with macrophage and T-cell recruitment in mdx skeletal muscle. Neuromuscular Disorders, Vol.13, pp. 223–35,

Porter, J.D.; Khanna, S.; Kaminski, H.J.; Rao, J.S.; Merriam, A.; Richmonds, C.R.; Leahy, P.; Li, J.; Guo, W. & Andrade, F.H. (2002). A chronic inflammatory response dominates the skeletal muscle molecular signature in dystrophin-deficient mdx mice. Human Molecular Genetics, Vol.11, pp. 263–72,

Praud, C.; Montarras, D.; Pinset,C. & Sebille, A. (2003). Dose effect relationship between the number of normal progenitor muscle cells grafted in mdx mouse skeletal striated muscle and the number of dystrophin-positive fibres. Neuroscience Letters, Vol.352, No.1, (Nov 27), pp. 70-2,

Quenneville, S.P.; Chapdelaine, P.; Skuk, D.; Paradis, M.; Goulet, M.; Rousseau, J.; Xiao, X.; Garcia, L. & Tremblay, J.P. (2007). Autologous transplantation of muscle precursor cells modified with a lentivirus for muscular dystrophy: human cells and primate models. Molecular Therapy, Vol.15, No.2, (Feb), pp. 431-8,

Radley, H.G.; Davies, M.J. & Grounds,M.D. (2008). Reduced muscle necrosis and long-term benefits in dystrophic mdx mice after cV1q (blockade of TNF) treatment. Neuromuscular Disorders, Vol.18, No.3, (Mar), pp. 227-38, ISSN 0960-8966

Rahim, A.A.; Wong, A.M.; Howe, S.J.; Buckley, S.M.; Acosta-Saltos, A.D.; Elston, K.E.; Ward, N.J.; Philpott, N.J.; Cooper, J.D.; Anderson, P.N.; Waddington, S.N.; Thrashe, A.J. & Raivich,G. (2009). Efficient gene delivery to the adult and fetal CNS using pseudotyped non-integrating lentiviral vectors. Gene Therapy, Vol.16, No. 4, (Apr), pp. 509-20, ISSN 0969-7128

Rando, T.A. &Blau, H.M. (1994). Primary mouse myoblast purification, characterization, and transplantation for cell-mediated gene therapy. The Journal of Cell Biology, Vol.125, No.6, (Jun), pp. 1275-87, ISSN 0021-9525

Reznick, A.Z.; Menashe, O.; Bar-Shai, M.; Coleman, R. & Carmeli, E. (2003). Expression of matrix metalloproteinases, inhibitor, and acid phosphatase in muscles of immobilized hindlimbs of rats. Muscle Nerve, Vol.27, No.1, (Jan), pp. 51-9, ISSN 0148-639X

Rodriguez, D.; Morrison, C.J. & Overall, C.M. (2010). Matrix metalloproteinases: what do they not do? New substrates and biological roles identified by murine models and proteomics. Biochimica Biophysica Acta, Vol.1803, No.1, (Jan), pp. 39-54, ISSN 0006-3002

Rosenberg, G.A. (2009). Matrix metalloproteinases and their multiple roles in neurodegenerative diseases. The Lancet Neurology, Vol.8, No.2, pp. 205-216,

www.intechopen.com

Page 30: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

438

Sacco, A.; Doyonnas, R.; Kraft, P.; Vitorovic, S. & Blau,H.M. (2008). Self-renewal and expansion of single transplanted muscle stem cells. Nature, Vol.456, No.7221, (Nov 27), pp. 502-6,

Sacco, A.; Mourkioti, F.; Tran, R.; Choi, J.; Llewellyn, M.; Kraft, P.; Shkreli, M.; Delp, S.; Pomerantz, J.H.; Artandi, S.E. & Blau, H.M. (2010). Short telomeres and stem cell exhaustion model Duchenne muscular dystrophy in mdx/mTR mice. Cell, Vol.143, No.7, (Dec 23), pp. 1059-71, ISSN 1097-4172

Sampaolesi, M.; Torrente, Y.; Innocenzi, A.; Tonlorenzi, R.; D'Antona, G.; Pellegrino, M.A.; Barresi, R.; Bresolin, N.; De Angelis, M.G.; Campbell, K.P.; Bottinelli, R. & Cossu, G. (2003). Cell therapy of alpha-sarcoglycan null dystrophic mice through intra-arterial delivery of mesoangioblasts. Science, Vol.301, No.5632, (Jul 25), pp. 487-92, ISSN 1095-9203

Sampaolesi, M.; Blot, S.; D'Antona, G.; Granger, N.; Tonlorenzi,R.; Innocenzi, A.; Mognol, P.; Thibaud, J.L.; Galvez ,B.G.; Barthelemy, I.; Perani, L.; Mantero, S.; Guttinger, M.; Pansarasa, O.; Rinaldi, C.; Cusella De Angelis, M.G.; Torrente, Y.; Bordignon, C.; Bottinelli, R. & Cossu, G. (2006). Mesoangioblast stem cells ameliorate muscle function in dystrophic dogs. Nature, Vol.444, No.7119, (Nov 30), pp. 574-9,

Sancricca, C.; Mirabella, M.; Gliubizzi, C.; Broccolini, A.; Gidaro, T. & Morosetti, R. (2010). Vessel-associated stem cells from skeletal muscle: From biology to future uses in cell therapy. World Journal of Stem Cells, Vol.2, No.3, (Jun 26), pp. 39-49, ISSN 1948-0210

Sciorati, C.; Galvez, B.G.; Brunelli, S.; Tagliafico, E.; Ferrari, S.; Cossu G.& Clementi, E. (2006). Ex vivo treatment with nitric oxide increases mesoangioblast therapeutic efficacy in muscular dystrophy. Journal of Cell Science, Vol.119,.Pt 24, (Dec 15), pp. 5114-23,

Seale, P.;. Sabourin, L.A; Girgis-Gabardo, A.; Mansouri, A.; Gruss, P. & Rudnicki, M.A. (2000). Pax7 is required for the specification of myogenic satellite cells. Cell, Vol.102, No.6, (Sep 15), pp. 777-86,

Sharma, K. & Ziyadeh,F.N. (1994). The emerging role of transforming growth factor-beta in kidney diseases. American Journal of Physiology Renal Physiology, Vol.266, pp. F829–F842.,

Shiomi, T.; Lemaitre, V.; D'Armiento, J. & Okada, Y. (2010). Matrix metalloproteinases, a disintegrin and metalloproteinases, and a disintegrin and metalloproteinases with thrombospondin motifs in non-neoplastic diseases. Pathology International, Vol.60, No.7, (Jul), pp. 477-96, ISSN 1440-1827

Silva-Barbosa, S.D.; Butler-Browne, G.S.; Di Santo, J.P. & Mouly, V. (2005). Comparative analysis of genetically engineered immunodeficient mouse strains as recipients for human myoblast transplantation. Cell Transplantation, Vol.14, No.7, pp. 457-67,

Skuk, D. & Tremblay, J.P. (2011). Intramuscular cell transplantation as a potential treatment of myopathies: clinical and preclinical relevant data. Expert Opinion on Biological Therapy, Vol.11, No.3, (Mar), pp. 359-74, ISSN 1744-7682

Skuk, D.; Roy, B.; Goulet, M. & Tremblay, J.P. (1999). Successful myoblast transplantation in primates depends on appropriate cell delivery and induction of regeneration in the host muscle. Experimental Neurology, Vol.155, No.1, (Jan), pp. 22-30, ISSN 0014-4886

Skuk, D.; Caron, N.; Goulet, M.; Roy, B.; Espinosa, F. & Tremblay, J.P. (2002). Dynamics of the early immune cellular reactions after myogenic cell transplantation. Cell Transplantation, Vol.11, No.7, pp. 671-81,

www.intechopen.com

Page 31: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

439

Smythe, G.M.; Fan, Y. & Grounds, M.D. (2000). Enhanced migration and fusion of donor myoblasts in dystrophic and normal host muscle. Muscle Nerve, Vol.23, No.4, (Apr), pp. 560-74, ISSN 0148-639X

Springer, T.A. (1994). Traffic signals for lymphocyte recirculation and leukocyte emigration: the multistep paradigm. Cell, Vol.76, No.2, (Jan 28), pp. 301-14, ISSN 0092-8674

Sternlicht, M.D. & Werb, Z. (2001). How matrix metalloproteinases regulate cell behavior. Annual Review of Cell and Developmental Biology, Vol.17, pp. 463-516, ISSN 1081-0706

Stevenson, E.J.; Giresi, P.G.; Koncarevic, A. & Kandarian, S.C. (2003). Global analysis of gene expression patterns during disuse atrophy in rat skeletal muscle. Journal of Physiology, Vol.551, Pt 1, (Aug 15), pp. 33-48, ISSN 0022-3751

Sugita, H. & Takeda, S. (2010). Progress in muscular dystrophy research with special emphasis on gene therapy. Proceedings of the Japan Academy. Series B, Physical and Biological sciences, Vol.86, No.7, pp. 748-56, ISSN 1349-2896

Sun, G.; Haginoya, K.; Chiba, Y.; Uematsu, M.; Hino-Fukuyo, N.; Tanaka, S.; Onuma, A.; Iinuma, K. & Tsuchiya,S. (2010). Elevated plasma levels of tissue inhibitors of metalloproteinase-1 and their overexpression in muscle in human and mouse muscular dystrophy. Journal of the Neurological Sciences, Vol.297, No.1-2, pp. 19-28,

Sun, G.; Haginoya, K.; Wu, Y.; Chiba, Y.; Nakanishi, T.; Onuma, A.; Sato, Y.; Takigawa, M.; Iinuma, K. & Tsuchiya, S. (2008). Connective tissue growth factor is overexpressed in muscles of human muscular dystrophy. Journal of Neurological Sciences, Vol.267, No.1, (04/15), pp. 48-56,

Tedesco, F.S.; Dellavalle, A.; Diaz-Manera, J.; Messina G. & Cossu, G. (2010). Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells. The Journal of Clinical Investigation, Vol.120, No.1, (Jan 4), pp. 11-9, ISSN 1558-8238

Torrente, Y.; El Fahime, E.; Caron, N.J.; Del Bo, R.; Belicchi, M.; Pisati, F.; Tremblay, J.P. & Bresolin, N. (2003). Tumor necrosis factor-alpha (TNF-alpha) stimulates chemotactic response in mouse myogenic cells. Cell Transplantation, Vol.12, No.1, pp. 91-100, ISSN 0963-6897

Torrente, Y.; Belicchi, M.; Sampaolesi, M.; Pisati, F.; Meregalli, M.; D'Antona, G.; Tonlorenzi, R.; Porretti, L.; Gavina, M.; Mamchaoui, K.; Pellegrino, M.A.; Furling, D.; Mouly, V.; Butler-Browne, G.S.; Bottinelli, R.; Cossu, G. & Bresolin, N. (2004). Human circulating AC133(+) stem cells restore dystrophin expression and ameliorate function in dystrophic skeletal muscle. The Journal of Clinical Investigation, Vol.114, No.2, (Jul), pp. 182-95,

Urso, M.L.; Szelenyi, E.R.; Warren, G. L. & Barnes, B. R. (2010). Matrix metalloprotease-3 and tissue inhibitor of metalloprotease-1 mRNA and protein levels are altered in response to traumatic skeletal muscle injury. European Journal Applied Physiology,Vol.109, No.5, pp. 963-72,

Vauchez, K.; Marolleau, J.P.; Schmid, M.; Khattar, P.; Chapel, A.; Catelain, C.; Lecourt, S.; Larghero, J.; Fiszman, M. & Vilquin, J.T. (2009). Aldehyde dehydrogenase activity identifies a population of human skeletal muscle cells with high myogenic capacities. Molecular Therapy, Vol.17, No.11, (Nov), pp. 1948-58, ISSN 1525-0024

Von Moers, A.; Zwirner, A.; Reinhold, A.; Bruckmann, O.; van Landeghem, F.; Stoltenburg-Didinger, G.; Schuppan, D.; Herbst, H. & Schuelke, M.. (2005). Increased mRNA expression of tissue inhibitors of metalloproteinase-1 and -2 in Duchenne muscular dystrophy. Acta Neuropathologica, Vol.109, No.3, (Mar), pp. 285-93, ISSN 0001-6322

www.intechopen.com

Page 32: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular Dystrophy

440

Vu, T.H. & Werb, Z. (2000). Matrix metalloproteinases: effectors of development and normal physiology. Genes & Development, Vol.14, No.17, (Sep 1), pp. 2123-33, ISSN 0890-9369

Wakeford, S.; Watt, D.J. & Partridge, T.A. (1991). X-irradiation improves mdx mouse muscle as a model of myofiber loss in DMD. Muscle Nerve, Vol.14, No.1, (Jan), pp. 42-50,

Wang, W.; Pan, H.; Murray, K.; Jefferson, B.S. & Li, Y. (2009). Matrix metalloproteinase-1 promotes muscle cell migration and differentiation. American Journal of Pathology, Vol.174, No.2, (Feb), pp. 541-9, ISSN 1525-2191

Webster, C. & Blau, H.M. (1990). Accelerated age-related decline in replicative life-span of Duchenne muscular dystrophy myoblasts: implications for cell and gene therapy. Somatic Cell Molecular Genetics, Vol.16, No.6, (Nov), pp. 557-65, ISSN 0740-7750

Wells, D.J.; Ferrer, A. & Wells, K.E. (2002). Immunological hurdles in the path to gene therapy for Duchenne muscular dystrophy. Expert Review Molecular Medicine,Vol.4, No.23, (Nov), pp. 1-23, ISSN 1462-3994

Wilson, C.A. & Cichutek, K. (2009). The US and EU regulatory perspectives on the clinical use of hematopoietic stem/progenitor cells genetically modified ex vivo by retroviral vectors. Methods in Molecular Biology,Vol.506, pp. 477-88,

Wittwer, M.; Flück, M.; Hoppeler, H.; Müller, S.; Desplanches D. & Billeter, R. (2002). Prolonged unloading of rat soleus muscle causes distinct adaptations of the gene profile. The FASEB Journal, Vol.16, pp. 884-886,

Yokota, T.; Lu, Q.L.; Morgan, J.E.; Davies, K.E.; Fisher, R.; Takeda, S. & Partridge, T.A. (2006). Expansion of revertant fibers in dystrophic mdx muscles reflects activity of muscle precursor cells and serves as an index of muscle regeneration. Journal of Cell Science, Vol.119, Pt 13, (Jul 1), pp. 2679-87,

Zanotti, S.; Gibertini, S.; & Mora. M. (2010). Altered production of extra-cellular matrix components by muscle-derived Duchenne muscular dystrophy fibroblasts before and after TGF-β1 treatment. Cell and Tissue Research, Vol.339, No.2, pp. 397-410,

Zanotti, S.; Saredi, S.; Ruggieri, A.; Fabbri, M.; Blasevich, F.; Romaggi, S.; Morandi, L. & Mora, M. (2007). Altered extracellular matrix transcript expression and protein modulation in primary Duchenne muscular dystrophy myotubes. Matrix Biology, Vol.26, No.8, (Oct), pp. 615-24, ISSN 0945-053X

Zhang, F.; Thornhill, S.I.; Howe, S.J.; Ulaganathan, M.; Schambach, A.; Sinclair, J.; Kinnon, C.; Gaspar, H.B.; Antoniou, M. & Thrasher, A.J. (2007). Lentiviral vectors containing an enhancer-less ubiquitously acting chromatin opening element (UCOE) provide highly reproducible and stable transgene expression in hematopoietic cells. Blood, Vol.110, No.5, (Sep 1), pp. 1448-57,

Zheng, B.; Cao, B.; Crisan, M.; Sun, B.; Li, G.; Logar, A.; Yap, S.; Pollett, J.B.; Drowley, L.; Cassino, T.; Gharaibeh, B.; Deasy, B.M.; Huard, J. & Peault, B. (2007). Prospective identification of myogenic endothelial cells in human skeletal muscle. Nature Biotechnology, Vol.25, No.9, (Sep), pp. 1025-34,

Zhou, L.; Porter, J.D.; Cheng, G.; Gong, B.; Hatala, D.A.; Merriam, A.P.; Zhou, X.; Rafael, J.A. & Kaminski, H.J. (2006). Temporal and spatial mRNA expression patterns of TGF-[beta]1, 2, 3 and T[beta]RI, II, III in skeletal muscles of mdx mice. Neuromuscular Disorders, Vol.16, No.1, (Jan), pp. 32-38,

www.intechopen.com

Page 33: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

Muscular DystrophyEdited by Dr. Madhuri Hegde

ISBN 978-953-51-0603-6Hard cover, 544 pagesPublisher InTechPublished online 09, May, 2012Published in print edition May, 2012

InTech EuropeUniversity Campus STeP Ri Slavka Krautzeka 83/A 51000 Rijeka, Croatia Phone: +385 (51) 770 447 Fax: +385 (51) 686 166www.intechopen.com

InTech ChinaUnit 405, Office Block, Hotel Equatorial Shanghai No.65, Yan An Road (West), Shanghai, 200040, China

Phone: +86-21-62489820 Fax: +86-21-62489821

With more than 30 different types and subtypes known and many more yet to be classified and characterized,muscular dystrophy is a highly heterogeneous group of inherited neuromuscular disorders. This book providesa comprehensive overview of the various types of muscular dystrophies, genes associated with each subtype,disease diagnosis, management as well as available treatment options. Though each different type andsubtype of muscular dystrophy is associated with a different causative gene, the majority of them haveoverlapping clinical presentations, making molecular diagnosis inevitable for both disease diagnosis as well aspatient management. This book discusses the currently available diagnostic approaches that haverevolutionized clinical research. Pathophysiology of the different muscular dystrophies, multifaceted functionsof the involved genes as well as efforts towards diagnosis and effective patient management, are alsodiscussed. Adding value to the book are the included reports on ongoing studies that show a promise forfuture therapeutic strategies.

How to referenceIn order to correctly reference this scholarly work, feel free to copy and paste the following:

Jennifer Morgan and Hala Alameddine (2012). Stem Cell Based Therapy for Muscular Dystrophies: Cell Typesand Environmental Factors Influencing Their Efficacy, Muscular Dystrophy, Dr. Madhuri Hegde (Ed.), ISBN:978-953-51-0603-6, InTech, Available from: http://www.intechopen.com/books/muscular-dystrophy/stem-cell-based-therapy-for-muscular-dystrophies-cell-types-and-environmental-factors-influencing-th

Page 34: Stem Cell Based Therapy for Muscular Dystrophies: Cell ...€¦ · 21 Stem Cell Based Therapy for Muscular Dystrophies: Cell Types and Environmental Factors Influencing Their Efficacy

© 2012 The Author(s). Licensee IntechOpen. This is an open access articledistributed under the terms of the Creative Commons Attribution 3.0License, which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.